BioAssay Ontology
type: Ontology
license: https://creativecommons.org/licenses/by-sa/4.0/
version info: 2.8.17
label: BAO
comment: Created by: Caty Chung, Nicolette Ross, Joan Glenny-Pescov, Jiaming Hu, Stephan Schurer*
comment: Contact: Stephan Schurer stephan dot schurer at med dot miami dot edu

percent cytotoxicity
type: Class
IAO_0000118: % cytotoxicity
IAO_0000115: It is a measure of the number of dead cells in a culture well. We consider it as a subclass of 'percent inhibition', because cell death is induced by inhibition of vital cellular processes and percent cytotoxicity increases as the number of dead cells increases. It can be estimated in the compound treated wells in comparison to vehicle-treated control wells and is expressed as a percent. The compound treatment is preferably performed in a short window of time to avoid masking the effect due to cell proliferation. Compound cytotoxicity is an important parameter to measure when developing potential human therapeutics. Cytotoxicity is determined as a measure of radioisotope (3H thymidine or 51Cr) release, lactate dehydrogenase release from damaged cells, tetrazolium salt and alamar blue reduction, fluorescent dyes that selectively stain live or dead cells, and decrease in ATP content. ATP levels are detected using a luminescence based assay kit such as CellTiter-Glo (Promega). ATP values higher than controls indicate proliferation and cultures with ATP concentrations lower than controls indicate cytotoxicity. Percent cytotoxicity = 100-percent viability
subclass of: percent inhibition

protein substrate and ligand constant
type: Class
IAO_0000115: They are used to express the binding interactions between labeled or unlabeled ligands with protein receptors and include Bmax, Kd, etc.
subclass of: endpoint

Bmax
type: Class
IAO_0000115: It is the amount of drug required to saturate a population of receptors and a measure of the number of receptors present in the sample. It is derived from Scatchard plot of binding data. It is analogous to Vmax in enzyme kinetics. The units of Bmax include cpm, sites/cell or fmol/mg. http://graphpad.com/curvefit/fitting_specific_binding_.htm
subclass of: binding constant

Kd
type: Class
IAO_0000115: Kd – is the equilibrium dissociation constant for a drug. It describes the affinity between a ligand (L) (such as a drug) and a protein (P). Ligand-protein affinities are influenced by non-covalent intermolecular interactions between the two molecules such as hydrogen bonding, electrostatic interactions, hydrophobic and Van der Waals forces. Kd = ([P] [L]) / [PL] The dissociation constant has molar units (M), which corresponds to the concentration of ligand [L] at which the binding site on a particular protein is half occupied, i.e. the concentration of ligand, at which the concentration of protein with ligand bound [PL], equals the concentration of protein with no ligand bound [P]. The smaller the dissociation constant, the more tightly bound the ligand is, or the higher the affinity between ligand and protein. http://www.graphpad.com/curvefit/law_of_mass_action.htm
subclass of: binding constant

mode of action
type: Class
IAO_0000118: MOA
IAO_0000115: This refers to the effect of the perturbagen on the target of an assay, whether it brings about inhibition, activation, cytotoxicity, etc.
subclass of: assay endpoint component

percent response
type: Class
IAO_0000118: % response
IAO_0000115: Percent increase or decrease of a predefined stimulus. Unit of Measure is always % when normalized to the dynamic range of the assay.
subclass of: response endpoint

ligand function mode of action
type: Class
IAO_0000115: Data measuring the biological effect of a compound, e.g. % cell death, activation of reporter gene expression, inhibition of enzyme activity, etc.
subclass of: mode of action

irreversible binding
type: Class
IAO_0000115: In this assay, the binding of the ligand to a receptor is permanent and cannot be dissociated by changing the binding conditions such as buffer, salt concentration, etc.
subclass of: ligand binding mode of action

reversible binding
type: Class
IAO_0000115: In this assay, the interaction of the ligand with a receptor can be dissociated by changing the binding conditions, e.g. buffer, salt concentration, etc.
subclass of: ligand binding mode of action

activation
type: Class
IAO_0000115: Increase of a predefined stimulus. Unit of Measure is always % when normalized to the dynamic range of the assay.
subclass of: ligand function mode of action

cytotoxicity
type: Class
IAO_0000115: It is the toxic or cell-death inducing property of a perturbagen. Known cytotoxic agents mediate cell death commonly by necrosis, apoptosis, or autophagy. Cytotoxicity can be detected by measuring various aspects of the death process: e.g. membrane permeability, ATP concentration, DNA fragmentation, etc.
subclass of: phenotypic mode of action

inhibition
type: Class
IAO_0000115: Reduction of a predefined stimulus. Unit of Measure is always % when normalized to the dynamic range of the assay.
subclass of: ligand function mode of action

stimulation
type: Class
IAO_0000115: Increase of a predefined stimulus. Unit of Measure is always % when normalized to the dynamic range of the assay.
subclass of: ligand function mode of action

growth inhibition
type: Class
IAO_0000115: Growth reduction of a predefined stimulus. Unit of Measure is always % when normalized to the dynamic range of the assay. As a measure of viable or proliferating cells, different researchers measure different parameters, namely, protein content (by sulforhodamine B staining followed by absorbance measurement), mitochondrial dehydrogenase activity (by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrasodium bromide, known as MTT staining followed by absorbance measurement), expression of proliferation associated antigens (by immunostaining for Ki-67), and ATP content (by using CellTiter-Glo reagent (Promega) followed by luminescence measurement.
subclass of: inhibition

percent growth inhibition
type: Class
IAO_0000118: % growth inhibition
IAO_0000115: % growth reduction of a predefined stimulus. Unit of Measure is always % when normalized to the dynamic range of the assay.
subclass of: percent inhibition

screening concentration
type: Class
IAO_0000115: The concentration of a perturbagen used in an assay to elicit the biological effect or perturbation. This typically assumes uniform / equal distribution of the perturbagen / compound in the assay system (typically a screening well).
subclass of: concentration endpoint

endpoint action correlation
type: Class
IAO_0000115: Endpoint action correlation describes weather a low or high endpoint value corresponds to low or high activity. Specifically if the endpoint value is positively or inversely correlated with the action that corresponds to the endpoint and which is specified as 'mode of action'. For example 'percent control' can be positively correlated with enzyme activity (remaining activity) and inversely correlated with the mode of action (function) inhibition depending on how the signal is normalized.
subclass of: assay endpoint component

positively correlated
type: Class
subclass of: endpoint action correlation

inversely correlated
type: Class
subclass of: endpoint action correlation

percent control
type: Class
IAO_0000115: Percent control is the response relative to a reference state, typically to a high control. For example it can describe (remaining) activity of a kinase (or e.g. kinase bound to substrate). Percent control could also quantify an inhibitory action depending on control and assay method.
subclass of: percent response

endpoint
type: Class
IAO_0000115: The endpoint is a quantitive or qualitative interpretable standardized representation of a perturbation (a change from a defined reference state of a "closed" model system) that is measured by the bioassay. An endpoint consists of a series of data points, one for each perturbing agent (screened entity) tested the assay.
subclass of: assay endpoint component
IAO_0000118: result
IAO_0000116: [BAO v 2.8.17 (Oct 2025)]

concentration endpoint
type: Class
IAO_0000115: It can refer to the screening concentration (for example in a primary assay) or it can be a concentration at which the perturbagen mediates a defined response, such as IC50 or EC50. It always has one value and a concentration unit.
subclass of: endpoint

response endpoint
type: Class
IAO_0000115: Reporting the extent / magnitude of the perturbation (induced by the perturbagen) such as percent inhibition. Response-type endpoints would typically be obtained from a single concentration perturbagen measurement.
subclass of: endpoint

AC50
type: Class
IAO_0000118: Potency
IAO_0000115: The effective concentration of a perturbagen, which produces 50% of the maximal possible response, which could mean either activation (EC50) or inhibition (IC50) for that perturbagen.
subclass of: concentration response endpoint

CC50
type: Class
IAO_0000115: The effective concentration of a cytotoxic compound, which produces 50% of the maximum possible cell death for that compound. Although the cytotoxic compound induces cell death, we define CC50 as subclass of IC50, because critical cellular processes are inhibited and CC50 is often used as a more specific description of IC50 for cell toxicity assays. Compound cytotoxicity is an important parameter to measure when developing potential human therapeutics. Cytotoxicity can be determined for example as a measure of radioisotope (3H thymidine or 51Cr) release, lactate dehydrogenase release from damaged cells, tetrazolium salt and alamar blue reduction, fluorescent dyes that selectively stain live or dead cells, or decrease in ATP content. ATP levels are detected using a luminescence based assay kit such as CellTiter-Glo (Promega). ATP values higher than controls (untreated cells) indicate proliferation and cultures with ATP concentrations lower than controls indicate cytotoxicity.
subclass of: concentration response endpoint

EC50
type: Class
IAO_0000115: The effective concentration of an agonist, which produces 50% of the maximum possible response for that agonist.
subclass of: concentration response endpoint

GI50
type: Class
IAO_0000118: growth inhibition by 50%
IAO_0000115: The effective concentration of a growth inhibitor, which produces 50% of the maximum possible response for that inhibitor. GI50 is calculated from [(Ti-Tz)/(C-Tz)] x 100 = 50, where Tz is absorbance at time zero, Ti is absorbance in the presence of test drug, and C is absorbance in the control (untreated cells). As a measure of viable or proliferating cells, different researchers measure different parameters, namely, protein content (by sulforhodamine B staining followed by absorbance measurement), mitochondrial dehydrogenase activity (by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrasodium bromide, known as MTT staining followed by absorbance measurement), expression of proliferation associated antigens (by immunostaining for Ki-67), and ATP content (by using CellTiter-Glo reagent (Promega) followed by luminescence measurement).
subclass of: concentration response endpoint

IC50
type: Class
IAO_0000115: The effective concentration of an inhibitor, which produces 50% of the maximum possible response for that inhibitor.
subclass of: concentration response endpoint

IC80
type: Class
IAO_0000115: The effective concentration of an inhibitor, which produces 80% of the maximum possible response for that inhibitor.
subclass of: concentration response endpoint

Ki
type: Class
IAO_0000115: Ki is the equilibrium inhibitor dissociation constant, the concentration of the competing inhibitor that results in binding to half the enzymes sites at equilibrium in the absence of substrate or other competitors. The Cheng and Prusoff equation: Ki - (IC50) / ( 1+ ([L]/Kd)) relates IC50 to Ki under conditions of competitive binding; Kd equilibrium dissociation constant of the (labeled) ligand, [L] ligand concentration. The Cheng and Prusoff equation: Ki - (IC50) / ( 1+ ([S]/Km)) relates IC50 to Ki under conditions of competitive inhibition; Ki equilibrium enzyme inhibitor dissociation constant; Km Michaelis-Menton constant, [S] substrate concentration.
subclass of: concentration response endpoint
subclass of: binding constant

fold change
type: Class
IAO_0000115: It is the ratio of biological activity in the presence of an exogenous substance to that in its absence. The fold change is useful when comparing test compounds evaluated across multiple functional assays because varying levels of efficacy can be observed amongst the different or same reference agonists.
subclass of: response endpoint

TGI
type: Class
IAO_0000118: total growth inhibition
IAO_0000115: TGI is total growth inhibition, which is the effective concentration of a growth inhibitor, which produces 0% relative growth for that inhibitor. Thus TGI signifies a cytostatic effect. tgi is calculated from [(Ti-Tz)/(C-Tz)] x 100 =0, where Ti = Tz and Tz is absorbance at time zero, Ti is absorbance in the presence of test drug, and C is absorbance in the control (untreated cells). As a measure of viable cells, different researchers measure different parameters, namely, protein content (by sulforhodamine B staining followed by absorbance measurement), mitochondrial dehydrogenase activity (by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrasodium bromide, known as MTT staining followed by absorbance measurement), and ATP content (by using CellTiter-Glo reagent (Promega) followed by luminescence measurement).
subclass of: concentration response endpoint

IC50 absolute
type: Class
IAO_0000115: Absolute IC50 (calculated from the curve-fit function) is the concentration corresponding to exactly 50 percent inhibition. It is obtained from the curve fit function (back-calculated IC50) and can also be extrapolated. Commonly the relative IC50 is reported; however in cell proliferation assays absolute IC50 is often used. The absolute IC50 can be more reproducible.
subclass of: IC50

IC50 relative
type: Class
IAO_0000115: The concentration of a test substance that produces an inhibitory effect corresponding to 50% of the activity of that particular substance (i.e. 50% of the difference between top and bottom of fitted curve). It can also be described as the concentration corresponding to the inflection point of the curve.
subclass of: IC50

pIC50
type: Class
IAO_0000118: -log IC50
IAO_0000115: pIC50 is -log IC50, where IC50 is the effective concentration of an inhibitor, which produces 50% of the maximum possible response for that inhibitor.
subclass of: IC50

percent activation
type: Class
IAO_0000118: % activation
IAO_0000115: Percent increase of a measureable response relative to some baseline. Unit of Measure is always % when normalized to the dynamic range of the assay. Percent activity measures the increased activity vs. an unperturbed state, i.e. percent activation := percent activity - 100; e.g. an agonist that results in twice the activity would have percent activity = 200 and percent activation = 100.
subclass of: percent response

percent inhibition
type: Class
IAO_0000115: Percent decrease of a measureable response as a consequence of compound treatment. Unit of Measure is always % when normalized to the dynamic range of the assay. Percent inhibition is expressed relative to a positive control (which results in total inhibition).
subclass of: percent response

percent cell viability
type: Class
IAO_0000118: % viability
IAO_0000115: It is a measure of living cells in a culture well. Unit of Measure is always % when normalized to the dynamic range of the assay. It can be estimated in the compound treated wells in comparison to vehicle-treated control wells and is expressed as a percent. Viability is determined by measuring tetrazolium salt and alamar blue reduction, staining with selective fluorescent dyes, or ATP content. ATP levels are detected using a luminescence based assay kit such as CellTiter-Glo (Promega). ATP values higher than controls indicate proliferation and cultures with ATP concentrations lower than controls indicates cytotoxicity. Percent viability = 100-percent cytotoxicity
subclass of: percent activity

signal increase corresponding to activation
type: Class
IAO_0000115: Increase in perturbation (reported by the endpoint mode of action, activation) is correlated to increase in signal.
subclass of: signal increase

signal decrease corresponding to inhibition
type: Class
IAO_0000115: Increase in perturbation (reported by the endpoint mode of action, inhibition) is correlated to decrease in signal.
subclass of: signal decrease

50 percent activation
type: Class
IAO_0000118: 50% activation
IAO_0000115: 50% increase of a predefined stimulus. Unit of Measure is always % when normalized to the dynamic range of the assay.
subclass of: percent activation

50 percent inhibition
type: Class
IAO_0000118: 50% inhibition
IAO_0000115: 50% reduction of a predefined stimulus. Unit of Measure is always % when normalized to the dynamic range of the assay.
subclass of: percent inhibition

80 percent inhibition
type: Class
IAO_0000118: 80% inhibition
IAO_0000115: 80% reduction of a predefined stimulus. Unit of Measure is always % when normalized to the dynamic range of the assay.
subclass of: percent inhibition

50 percent cell viability
type: Class
IAO_0000118: 50% viability
IAO_0000115: Assay has 50% living cells. Unit of Measure is always % when normalized to the dynamic range of the assay.
subclass of: percent cell viability

fold activation
type: Class
IAO_0000115: The ratio of biological activity in the presence of an exogenous substance to that in its absence. This result type is used exclusively with single point (screening concentration) assays.
subclass of: fold change

fold inhibition
type: Class
IAO_0000115: The ratio of biological activity in the absence of an exogenous substance to that in its presence. This result type is used exclusively with single point (screening concentration) assays.
subclass of: fold change

B-score
type: Class
IAO_0000115: The B score is an analog of the Z score, but is more resistant to the presence of outliers and to differences in the measurement error distributions of the compounds. It is calculated by first computing a two-way median to account for row and column effects of the plate, which is then divided by their median absolute deviation to standardize for plate-to-plate variability.
subclass of: statistical endpoint

Z-score
type: Class
IAO_0000115: Random and systematic error can induce either underestimation (false negatives) or overestimation (false positives) of measured signals. Z score indicates how many standard deviations an observation is above or below the mean. For calculating this, the average of the plate values is subtracted from individual raw values and the difference divided by the standard deviation estimated from all measurements of the plate.
subclass of: statistical endpoint

curve fit specification
type: Class
IAO_0000115: Has curve fit parameters, curve fit method, properties like Hill coefficient, concentration range, and measurement repetition. It involves capturing the trend in the data by assigning a single function across the entire range. The goal of curve fitting is to find the parameter values that most closely match the data.
subclass of: assay endpoint component

Hill equation
type: Class
IAO_0000115: The Hill equation is commonly used to estimate the number of ligand molecules that are required to bind to a receptor to produce a functional effect. The Hill coefficient can be considered as an interaction coefficient, reflecting the extent of cooperativity among multiple ligand binding sites.
subclass of: curve fit model

competitive binding
type: Class
IAO_0000115: An assay based on the competition between a labeled and an unlabeled ligand in the reaction with a receptor binding agent (e.g. antibody, receptor, transport protein).
subclass of: ligand binding mode of action

non-competitive binding
type: Class
IAO_0000115: Non-competitive ligands interact with receptors at sites distinct from the competitive ligand binding pocket, conferring multiple modes of action.
subclass of: ligand binding mode of action

input data
type: Class
IAO_0000115: It identifies whether the data has been normalized (by Z and Z' factors, signal to background, signal to noise, and coefficient of variance), or if it was an immediate readout obtained from a HTS assay.
subclass of: curve fit specification

normalized data
type: Class
IAO_0000115: Data can be normalized by Z and Z' factors, signal to background, signal to noise, and coefficient of variance. Plate based normalization is usually based on controls. In the absence of controls, the Z-score can be used to normalize the data by plate.
subclass of: input data

raw data
type: Class
IAO_0000115: The readout obtained from a HTS assay which includes measurements from the positive and negative control wells in each plate. This is the data that needs to be processed.
subclass of: input data

ligand binding mode of action
type: Class
IAO_0000115: Concepts describing the type of perturbagen interaction with the receptor.
subclass of: mode of action

km
type: Class
IAO_0000115: The concentration of substrate at ½ Vmax, according to the Henri-Michaelis-Menten kinetic model.
subclass of: enzyme kinetic constant

koff
type: Class
IAO_0000115: The off-rate associated with the release of inhibitor from an enzyme-inhibitor complex.
subclass of: enzyme kinetic constant

kon
type: Class
IAO_0000115: The on-rate associated with the formation of an enzyme-inhibitor complex.
subclass of: enzyme kinetic constant

kcat
type: Class
IAO_0000115: Turnover number representing the maximum number of substrate molecules converted to products per active site per unit time.
subclass of: enzyme kinetic constant

competitive inhibition
type: Class
IAO_0000115: A competitive inhibitor binds only to free enzyme. Often this binding event occurs on the active site of the target, precisely where substrate also binds. It will raise the apparent KM value for its substrate with no change in the apparent Vmax value. As a result, competitive inhibition can be overcome, observed by an increase in the apparent KI value, at higher concentrations of substrate.
subclass of: inhibition

uncompetitive inhibition
type: Class
IAO_0000115: An uncompetitive inhibitor binds exclusively to the enzyme-substrate complex yielding an inactive enzyme-substrate-inhibitor complex. When encountered, the apparent Vmax value and the apparent KM value should both decrease.
subclass of: inhibition

non-competitive inhibition
type: Class
IAO_0000115: A noncompetitive inhibitor binds equally well to both free enzyme and the enzyme-substrate complex. These binding events occur exclusively at a site distinct from the precise active site occupied by substrate. It will lower the apparent Vmax value, yet there is no effect on the apparent KM value for its substrate. Essentially, the KI of the inhibitor does not change as a function of the substrate concentration.
subclass of: inhibition

enzyme kinetic constant
type: Class
IAO_0000115: Describe kinetics of enzyme-catalyzed reactions. It includes the enzyme kinetic constants namely, Km and Vmax, which help to model the time course of disappearance of substrate and the production of product.
subclass of: protein substrate and ligand constant

partial inhibition
type: Class
IAO_0000115: Partial inhibition results from the formation of an enzyme-substrate-inhibitor complex that can generate product with less efficiency than the enzyme-substrate complex.
subclass of: inhibition

allosteric modulation
type: Class
IAO_0000115: An allosteric effector operates to enhance active site substrate affinity and/or catalysis. An allosteric inhibitor decreases activity by binding to an allosteric site, other than or in addition to the active site on the target. This interaction is characterized by a conformational change in the target enzyme that is required for inhibition.
subclass of: modulation

tight binding inhibition
type: Class
IAO_0000115: In this type of inhibition, the population of free, soluble inhibitor is significantly depleted by the formation of the enzyme-inhibitor or enzyme-substrate-inhibitor complex. While tight-binding inhibitors can bind to the target enzyme in a competitive, noncompetitive, or uncompetitive manner with respect to substrate binding, they can display noncompetitive phenotypes.
subclass of: inhibition

time dependent inhibition
type: Class
IAO_0000115: Time-dependent inhibitors bind slowly to the enzyme on the time scale of enzymatic turnover, and thus display a change in initial velocity with time. This has the effect of slowing the observed onset of inhibition.
subclass of: inhibition

signal direction
type: Class
IAO_0000115: It is the trend of measured readout signal, whether it increases or decreases in perturbagen treated wells, as compared to the untreated or carrier-treated wells and the endpoint mode of action of an assay.
subclass of: assay endpoint component

saturation binding
type: Class
IAO_0000115: These experiments measure specific radioligand binding at equilibrium at various concentrations of the radioligand.
subclass of: ligand binding mode of action

Tm
type: Class
IAO_0000118: melting temperature
IAO_0000115: Tm is defined as the midpoint temperatuere of the protein unfolding transition. It is determined by generating a thermal denaturation curve for the target molecule and taking the midpoint temperature between folding and unfolding state of the protein. In nucleic acid thermodynamics, it is the temperature at which 50% of the DNA strands and its perfect complement are in duplex.
subclass of: temperature endpoint

raw activity
type: Class
IAO_0000115: Raw or qualitative data are reported as endpoints in an assay, e.g., luminescence counts, fluorescence intensity, etc.
subclass of: response endpoint

temperature endpoint
type: Class
IAO_0000115: The types of endpoints that report changes in temperature as a measure of a biological reaction, e.g. tm.
subclass of: endpoint

vmax
type: Class
IAO_0000115: Vmax is defined as the maximum initial velocity of an enzyme catalyzed reaction under the given conditions, and it is measured in units of quantity of substrate transformed per unit time for a given concentration of enzyme.
subclass of: enzyme kinetic constant

binding constant
type: Class
IAO_0000115: This endpoint type describes the bonding affinity between two molecules at equilibrium, e.g., drug-receptor interaction.
subclass of: protein substrate and ligand constant

50 percent cytotoxicity
type: Class
IAO_0000115: The perturbagen mediated 50% of cells to die in an assay.
subclass of: percent cytotoxicity

EC30
type: Class
IAO_0000115: The effective concentration of an agonist, which produces 30% of the maximum possible response for that agonist.
subclass of: concentration response endpoint

PubChem endpoint name
type: Class
IAO_0000115: It is the term that describes an endpoint or result of a bioassay, which is deposited at PubChem.
subclass of: assay endpoint component

curve fit model
type: Class
IAO_0000115: A mathematical model / equation to which the data is fitted (using the curve fit method / algorithm).
subclass of: curve fit specification

3 parameter Hill equation
type: Class
subclass of: Hill equation

4 parameter Hill equation
type: Class
subclass of: Hill equation

efficacy
type: Class
IAO_0000118: Efficacy
IAO_0000115: The maximum response that can be achieved with the perturbagen as percentage of the positive control.
subclass of: percent response

maximal inhibition
type: Class
IAO_0000115: Maximum inhibition of an antagonist or inhibitor (relative an efficacious positive control)
subclass of: efficacy

maximal activation
type: Class
IAO_0000115: The maximum percent activation of an agonist
subclass of: efficacy

percent activity
type: Class
IAO_0000115: Percent activity is the response relative to an unperturbed state; in case of inhibition the interpretation is that of remaining activity, i.e. percent inhibition := 100 - percent activity.
subclass of: percent response

50 percent growth inhibition
type: Class
subclass of: percent growth inhibition

100 percent growth inhibition
type: Class
subclass of: percent growth inhibition

EC20
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: concentration response endpoint

EC150
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: concentration response endpoint

EC90
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: concentration response endpoint

IC95
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: concentration response endpoint

MIC80
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: concentration response endpoint

MIC90
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: concentration response endpoint

ED
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: dosage endpoint

ED25
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: dosage endpoint

ED30
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: dosage endpoint

ED90
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: dosage endpoint

LD10
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: dosage endpoint

ID50
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: dosage endpoint

MinED
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: dosage endpoint

MTD
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: dosage endpoint

TD50
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: dosage endpoint

maximal effect
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: efficacy

Increase
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: percent response

percent change
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: percent response

percent growth
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: percent response

percent protection
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: percent response

percent remaining
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: percent response

uptake
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: percent response

efflux ratio
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: physical property endpoint

Kinactivation
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: binding constant
IAO_0000115: maximum rate of inactivation
IAO_0000118: kinact
submitted by: https://github.com/Scientist328455
has xref: https://doi.org/10.1177/1087057116671509

residence time
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: time endpoint

T
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: time endpoint

ED80
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: dosage endpoint

EC10
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: concentration response endpoint

EC25
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: concentration response endpoint

IC75
type: Class
comment: IRI prefix change from BAO_02000 to BAO_00012 in January 2017
subclass of: concentration response endpoint

negative allosteric modulation
type: Class
subclass of: allosteric modulation

positive allosteric modulation
type: Class
subclass of: allosteric modulation

percent apoptotic cells
type: Class
IAO_0000115: The percentage of cells in an assay that show the hallmarks of 'programmed cell death' or apoptosis, namely, membrane asymmetry, caspase activation, nuclear fragmentation, etc.
subclass of: percent cytotoxicity

percent mitotic cells
type: Class
IAO_0000115: This represents the percentage of cells in a cell population that are in the M phase of the cell cycle. The cells in this phase can be detected using various markers, one of which is the characteristic phosphorylation of certain proteins that stain positive with MPM2 antibody.
subclass of: percent activity

percent interphase cells
type: Class
comment: 'has marker' some (not ('DEVD-NucView 488' or 'LysoTracker Red' or 'Hoechst 33342'))
IAO_0000115: This represents the percentage of cells in a cell population that are preparing for cell division and that exist in either G1, S or G2 phases of the cell cycle. This is calculated by subtracting from the total cell number, the number of cells in the M phase, apoptotic and dead cells in an assay plate.
subclass of: percent activity

percent DNA replicated cells
type: Class
IAO_0000115: This represents the percentage of cells in a cell population that have undergone the S phase (completed DNA replication) in preparation for mitosis, as indicated by staining positive for EdU.
subclass of: percent activity

percent dead cells
type: Class
comment: 'has marker' some ('Hoechst 33342' and not ('DEVD-NucView 488' or 'LysoTracker Red') )
IAO_0000115: The percentage of cells in an assay that are no longer alive (viable), and show the characteristic features, such as staining with propidium iodide, blurry staining with DAPI, etc.
subclass of: percent cytotoxicity

percent G2 arrested cells
type: Class
IAO_0000115: This represents the percentage of cells in a cell population that have undergone the DNA synthesis in the S phase as indicated by staining positive for EdU, but have not undergone the M phase as they stained negative for MDM2. In other words, these cells were arrested in the G2/M cell cycle check-points after treatment with the respective perturbagen in the assay.
subclass of: percent activity

percent non-arrested cells
type: Class
IAO_0000115: This represents the percentage of cells in a cell population that have completed the mitotic cell cycle, and that have stained positive for both S phase (EdU) and M phase (MDM2) markers. In other words, these cells were not arrested in any of the cell cycle check-points after treatment with the respective perturbagen in the assay.
subclass of: percent activity

time endpoint
type: Class
IAO_0000115: An endpoint defined by a length in time at which a desired effect or observation occurs.
subclass of: endpoint

T1/2
type: Class
IAO_0000115: Half-life of drug is the time taken for the concentration of the drug to decrease by half.
subclass of: time endpoint

dosage endpoint
type: Class
IAO_0000115: An endpoint defined an effect seen in animals at a particular dosage, typically defined as a ratio of treatment to animal mass (e.g., mg/kg).
subclass of: concentration endpoint

LD50
type: Class
IAO_0000118: lethal dose 50%
IAO_0000115: The median lethal dose is the dose required to kill (produce lethality) in 50% of tested population.
subclass of: dosage endpoint

graphical calculation endpoint
type: Class
IAO_0000115: An endpoint derived from calculus-based analysis of graphical measures.
subclass of: endpoint

Cmax
type: Class
IAO_0000115: The maximal concentration of a drug achieved following administration (maximum point of a concentration-time curve).
subclass of: graphical calculation endpoint

AUC
type: Class
IAO_0000118: area under curve
IAO_0000115: It is the area under the drug concentration-time curve (AUC) following a single dose or at steady state, and is expressed as weight*time/volume.
subclass of: graphical calculation endpoint

slope
type: Class
IAO_0000115: Slope is described as the ratio of the change in y-axis divided by the change in x-axis between two points on a line or a curve. m= y2-y1 / x2-x1
subclass of: graphical calculation endpoint

amplification curve calculated endpoint
type: Class
IAO_0000115: Endpoint values derived from an exponential growth curve, such as in a PCR reaction.
subclass of: graphical calculation endpoint

Cp
type: Class
IAO_0000118: crossing point
IAO_0000115: Crossing point- In an exponential amplification curve (i.e., qPCR amplification) the value in number of amplification cycles at which the signal enters log phase, as determined by the maximal second derivative of the curve.
subclass of: amplification curve calculated endpoint

Cq
type: Class
IAO_0000118: quantificatoin cycle
IAO_0000115: Quantificatoin cycle; general term, whether defined by Cp or Ct, for the value of interest determined from an exponential amplification curve (such as number of cycles in a PCR reaction).
subclass of: amplification curve calculated endpoint

Ct
type: Class
IAO_0000118: threshold cycle
IAO_0000115: Crossing threshold; in an exponential amplification curve (i.e., qPCR amplification) the value in number of amplification cycles at which the signal crosses a defined threshold.
subclass of: amplification curve calculated endpoint

statistical endpoint
type: Class
IAO_0000115: Endpoint values determined by a statistical measurement of the signal relative to the populations of signals observed.
subclass of: response endpoint

MAD score
type: Class
IAO_0000115: The number of median absolute deviations outside the median of control or compound wells.
subclass of: statistical endpoint

physical property endpoint
type: Class
IAO_0000115: A measurement of an intrinsic property of a molecular entity.
subclass of: endpoint

logD
type: Class
IAO_0000115: Logarithm (log10) of the Distribution Coefficient, D, which is defined as the ratio of concentrations of a small molecule / drug distributed between octanol and water. LogD refers to the distribution of all forms of a compound between the two immiscible phases at equilibrium. It depends on pH of the aqueous phase, which is buffered to a specific value. A larger logD means the compound / drug is more hydrophobic (greasy) and a lower logD corresponds to better solubility in water.
subclass of: physical property endpoint

logP
type: Class
IAO_0000115: Logarithm (log10) of the Partition Coefficient, P, which is defined as ratio of concentrations of a small molecule / drug distributed in octanol and water. LogP refers to the distribution of un-ionized (neutral species of) compound between the two immiscible phases at equilibrium; the pH is adjusted such that the major microspecies is the un-ionized form. A larger logP means the compound / drug is more hydrophobic (greasy) and a lower logP corresponds to better solubility in water.
subclass of: physical property endpoint

pKa
type: Class
IAO_0000115: pKa is the negative log10 of the acid dissociation constant (Ka) of a molecule. Ka is the equilibrium constant for dissociation of the protonated base (acid) into the free base and a proton (hydromium ion).
subclass of: physical property endpoint

percent purity
type: Class
IAO_0000115: Percent purity is the ratio of mass of pure compound to the actual mass of the available/vendor supplied compound, multiplied by 100. The majority of compounds and elemental substances are only available with a larger or smaller amount of impurities, which contribute to the mass of the impure compound.
subclass of: physical property endpoint

apical‑to‑basolateral permeability (A > B)
type: Class
IAO_0000115: Measurement of compound transport across a polarized epithelial monolayer from the apical to the basolateral side, typically reported as Papp (cm/s)
subclass of: apparent permeability coefficient (Papp)
IAO_0000118: A‑to‑B permeability
IAO_0000118: absorptive permeability
IAO_0000118: apical > basolateral
IAO_0000119: https://doi.org/10.14573/altex.2403271
IAO_0000116: [BAO v 2.8.17 (Oct 2025)]

basolateral‑to‑apical permeability (B > A)
type: Class
IAO_0000115: Measurement of compound transport across a polarized epithelial monolayer from the basolateral to the apical side, typically reported as Papp (cm/s)
subclass of: apparent permeability coefficient (Papp)
IAO_0000118: B‑to‑A permeability
IAO_0000118: basolateral > apical
IAO_0000118: secretory permeability
IAO_0000118: efflux‑directional permeability
IAO_0000119: https://doi.org/10.14573/altex.2403271
IAO_0000116: [BAO v 2.8.17 (Oct 2025)]

solubility
type: Class
IAO_0000115: The ability of a chemical substance to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution. The solubility of a given substance is dependent on the solvent used, as well as on temperature and pressure.
subclass of: physical property endpoint

profile endpoint
type: Class
IAO_0000115: An endpoint defined by a set of measurements from a multiparametric assay. The set of measurements may be aggregated to an overall profile score, weighting each measurment in the profile relative to a desired outcome.
subclass of: endpoint

computational profile endpoint
type: Class
subclass of: profile endpoint

gene-expression profile endpoint
type: Class
subclass of: profile endpoint

panel-assay profile endpoint
type: Class
subclass of: profile endpoint

IC90
type: Class
IAO_0000115: The effective concentration of an inhibitor, which produces 90% of the maximum possible response for that inhibitor.
subclass of: concentration response endpoint

LC50
type: Class
IAO_0000115: It is 50% lethal concentration (the concentration that kills 50% of treated cells).
subclass of: concentration response endpoint

MIC
type: Class
IAO_0000118: minimum inhibitory concentration
IAO_0000115: The lowest concentration of an inhibitor (antimicrobial agent) required to inhibit the growth of a microorganism.
subclass of: concentration response endpoint

percent bound
type: Class
IAO_0000115: It is a measure of the amount of radioligand that binds to its receptor in a competitive binding assay. It is the ratio of the bound to the total bound, where bound refers to the reading obtained from a binding reaction involving radioligand, receptor and a cold competitor ligand, while total bound is the reading obtained in the absence of any added competitor.
subclass of: percent response

percent recovery
type: Class
IAO_0000115: In a purification assay, percent recovery is the ratio of mass of the entity obtained after the affinity purification to the mass of the unpurified entity originally added in the assay, multiplied by 100.
subclass of: percent response

signal decrease corresponding to activation
type: Class
IAO_0000115: Increase in perturbation (reported by the endpoint mode of action, activation) is correlated to decrease in signal.
subclass of: signal decrease

signal increase corresponding to inhibition
type: Class
IAO_0000115: Increase in perturbation (reported by the endpoint mode of action, inhibition) is correlated to increase in signal.
subclass of: signal increase

concentration response endpoint
type: Class
subclass of: concentration endpoint

pEC50
type: Class
IAO_0000118: -log EC50
IAO_0000115: pEC50 is -logEC50, where EC50 is the effective concentration of an agonist, which produces 50% of the maximum possible response for that agonist.
subclass of: EC50

90 percent inhibition
type: Class
IAO_0000118: 90% inhibition
IAO_0000115: 90% reduction of a predefined stimulus. Unit of Measure is always % when normalized to the dynamic range of the assay.
subclass of: percent inhibition

measured concentration
type: Class
IAO_0000115: Measured / detected concentration of the perturbagen / compound in the assay or a subsystem (locally) in the assay. For example measured absolute concentration in the brain. This is in contrast to screening concentration, which is the (final assumed) concentration of a compound added to the assay.
subclass of: concentration endpoint

volume endpoint
type: Class
subclass of: endpoint

clearance
type: Class
IAO_0000118: Drug clearance
IAO_0000115: Clearance is defined as the volume of plasma cleared of a drug over a specified time period.
subclass of: volume endpoint
IAO_0000118: CL
IAO_0000118: drug clearance
IAO_0000119: https://www.ncbi.nlm.nih.gov/books/NBK557758
IAO_0000116: [BAO v 2.8.17 (Oct 2025)]

T1/2(in vivo)
type: Class
IAO_0000115: The time taken for the concentration of the drug in a particular tissue or blood plasma to decrease by half.
subclass of: T1/2

T1/2(in vitro)
type: Class
IAO_0000115: The time taken for the concentration of the drug in an in-vitro system (e.g., liver microsomes) to decrease by half.
subclass of: T1/2

AUC(oral)
type: Class
IAO_0000115: The area under the drug concentration-time curve following an oral dose.
subclass of: AUC

AUC(iv)
type: Class
IAO_0000115: The area under the drug concentration-time curve following an intravenous dose.
subclass of: AUC

CL(renal)
type: Class
IAO_0000115: Clearance of the drug due to renal excretion.
subclass of: clearance

CL(hepatic)
type: Class
IAO_0000115: Clearance of the drug due to hepatic enzyme activity and biliary excretion.
subclass of: clearance

aqueous solubility
type: Class
IAO_0000115: The ability of a chemical substance to dissolve in water.
subclass of: solubility

fold increase
type: Class
subclass of: fold change

fold decrease
type: Class
subclass of: fold change

percent mitotic arrested cells
type: Class
subclass of: percent activity

apparent permeability coefficient (Papp)
type: Class
subclass of: physical property endpoint
IAO_0000118: Papp
IAO_0000115: A rate measure of how quickly a compound crosses a biological or artificial membrane, expressed in centimeters per second (cm/s), calculated from the transport rate normalized to membrane area and donor concentration
IAO_0000119: https://doi.org/10.1007/s10928-008-9086-4
IAO_0000116: [BAO v 2.8.17 (Oct 2025)]

Ka
type: Class
subclass of: concentration response endpoint
subclass of: binding constant

EC 5 hour
type: Class
IAO_0000115: The concentration of compound that elicits an extension of circadian period length by 5 hours.
subclass of: concentration response endpoint

AC1000 absolute
type: Class
IAO_0000115: The compound concentration at which the fitted curve passes activity threshold 1000.
subclass of: concentration response endpoint

AC10 absolute
type: Class
IAO_0000115: The compound concentration at which the fitted curve passes activity threshold 10.
subclass of: concentration response endpoint

AC26 absolute
type: Class
IAO_0000115: The compound concentration at which the fitted curve passes activity threshold 26.
subclass of: concentration response endpoint

AC35 absolute
type: Class
IAO_0000115: The compound concentration at which the fitted curve passes activity threshold 35.
subclass of: concentration response endpoint

AC40 absolute
type: Class
IAO_0000115: The compound concentration at which the fitted curve passes activity threshold 40.
subclass of: concentration response endpoint

AC500 absolute
type: Class
IAO_0000115: The compound concentration at which the fitted curve passes activity threshold 500.
subclass of: concentration response endpoint

ECMax
type: Class
IAO_0000115: The compound concentration whereupon perceived activity reaches the maximum value observed (with a positive control).
subclass of: concentration response endpoint

ECMax_Tm
type: Class
IAO_0000115: The compound concentration whereupon perceived activity (change in Tm) reaches the maximum value observed (with a positive control).
subclass of: ECMax

ECMax_Agonist
type: Class
IAO_0000115: The agonist concentration whereupon perceived activity reaches the maximum value observed (with a positive control).
subclass of: ECMax

ECMax_fold increase
type: Class
IAO_0000115: The compound concentration whereupon perceived activity (fold increase) reaches the maximum value observed (with a positive control).
subclass of: ECMax

ECMax_percent inhibition
type: Class
IAO_0000115: The compound concentration whereupon perceived activity (percent inhibition) reaches the maximum value observed (with a positive control).
subclass of: ECMax

agonism
type: Class
subclass of: ligand function mode of action

antagonism
type: Class
subclass of: ligand function mode of action

allosteric inhibition
type: Class
subclass of: inhibition

partial activation
type: Class
subclass of: activation

allosteric activation
type: Class
IAO_0000115: Small molecule that can bind to sites other than the receptor active site and affect activity of the receptor.
subclass of: activation

modulation
type: Class
subclass of: ligand function mode of action

allosteric agonism
type: Class
subclass of: agonism

partial agonism
type: Class
subclass of: agonism

full agonism
type: Class
subclass of: agonism

inverse agonism
type: Class
subclass of: agonism

full activation
type: Class
subclass of: activation

MIC50
type: Class
IAO_0000115: The lowest concentration of an antimicrobial agent required to inhibit the growth of 50% of organisms.
subclass of: concentration response endpoint

ED50
type: Class
IAO_0000115: It is the dose that produces an effect in 50% of the tested population, or the dose required to produce half-maximal response.
subclass of: dosage endpoint

Tmax
type: Class
IAO_0000115: The time required for a drug to reach maximum concentration in plasma (Cmax) following administration.
subclass of: time endpoint

pA2
type: Class
IAO_0000115: The negative logarithm (log10) of the molar concentration of antagonist which requires the agonist concentration to be doubled in order to achieve the original response.
subclass of: concentration response endpoint

IZ
type: Class
IAO_0000118: Inhibition zone
IAO_0000115: In the disk diffusion susceptibility test, the zone of inhibition is the clear area surrounding an antimicrobial disk where bacterial growth is inhibited, usually measured as a diameter. The diameter of the zone of inhibition is proportional to the susceptibility of the organism tested.
subclass of: graphical calculation endpoint

Vd
type: Class
IAO_0000118: Volume of distribution
IAO_0000115: Volume of Distribution is defined as the theoretical volume in which the total drug administered would need to be distributed to produce the concentration that is observed in plasma. Measured as the total amount of drug in the body divided by the concentration of drug in the plasma.
subclass of: volume endpoint

Vdss
type: Class
IAO_0000118: Volume of distribution at steady state
IAO_0000115: The theoretical volume in which the total drug administered would need to be distributed to produce the concentration that is observed in plasma at steady state i.e when the rate of change of amount of drug in the body is zero. VdSS is proportional to the amount of drug in the body versus the plasma concentration of the drug at steady state (pseudo-equilibrium).
subclass of: volume endpoint

F
type: Class
IAO_0000118: BA
IAO_0000118: Bioavailability
IAO_0000115: Bioavailability is a subcategory of absorption and is the fraction (or %) of unchanged drug that reaches the systemic circulation, thereby accessing the site of action. It is usually determined as the ratio of AUC(oral)/AUC(iv).
subclass of: graphical calculation endpoint

assay endpoint component
type: Class
label: assay result component

allosteric antagonism
type: Class
subclass of: antagonism

definitive CYP IC50
type: Class
IAO_0000118: definitive CYP IC50
subclass of: IC50
submitted by: SEED Project - Pistoia Alliance

IC20
type: Class
IAO_0000115: The effective concentration of an inhibitor, which produces 20% of the maximum possible response for that inhibitor.
subclass of: concentration response endpoint

IC25
type: Class
IAO_0000115: The effective concentration of an inhibitor, which produces 25% of the maximum possible response for that inhibitor.
subclass of: concentration response endpoint

IC30
type: Class
IAO_0000115: The effective concentration of an inhibitor, which produces 30% of the maximum possible response for that inhibitor.
subclass of: concentration response endpoint

phenotypic mode of action
type: Class
subclass of: mode of action

neurite blebbing
type: Class
subclass of: phenotypic mode of action

neurite branching
type: Class
subclass of: phenotypic mode of action

neurite outgrowth
type: Class
IAO_0000118: neurite elongation
subclass of: phenotypic mode of action

neurite shortening
type: Class
subclass of: phenotypic mode of action

axon bundle defasciculation
type: Class
subclass of: phenotypic mode of action

axon fasciculation
type: Class
subclass of: phenotypic mode of action

fragments per kilobase of exon per million mapped reads
type: Class
IAO_0000118: FPKM
subclass of: gene-expression profile endpoint

NF-KappaB p65 translocation
type: Class
comment: need to be reviewed
subclass of: phenotypic mode of action

percent neurite outgrowth
type: Class
subclass of: percent activity

percent neurite count
type: Class
subclass of: percent activity

percent neurite branch point
type: Class
subclass of: percent activity

TC50
type: Class
IAO_0000119: PubChem AID: 2649
IAO_0000116: Date from BAE: 6/22/2016
IAO_0000115: The concentration of compound required to kill 50% of a cell population (i.e., 50% inhibitory concentration in a cytotoxicity assay).
subclass of: concentration response endpoint

TCID50
type: Class
IAO_0000119: PubChem AID: 2024
IAO_0000116: Date from BAE: 7/21/2016
IAO_0000115: 50% Tissue Culture Infective Dose (TCID50) is the measure of infectious virus titer. This endpoint dilution assay quantifies the amount of virus required to kill 50% of infected hosts or to produce a cytopathic effect in 50% of inoculated tissue culture cells.
subclass of: concentration response endpoint

reversible inhibition
type: Class
IAO_0000119: PubChem AID: 588831
IAO_0000116: Date from BAE: 7/19/2016
subclass of: inhibition

binary endpoint
type: Class
subclass of: categorical endpoint
IAO_0000119: PubChem AID: 449752
IAO_0000116: Date from BAE: 5/30/2016
IAO_0000115: Any result reported as a simple binary assessment, such as 'active/ inactive', 'true/ false', etc.

signal decrease
type: Class
subclass of: signal direction

signal increase
type: Class
subclass of: signal direction

protein level
type: Class
subclass of: profile endpoint

quantified endpoint
type: Class
deprecated: true
subclass of: endpoint

quantified entity
type: Class

metabaloid profile
type: Class
subclass of: profile endpoint

Cell Painting Profile
type: Class
subclass of: profile endpoint

epigenetic profile
type: Class
subclass of: computational profile endpoint

cell profile
type: Class
subclass of: gene-expression profile endpoint

beta-arrestin clustering assay
type: Class
IAO_0000115: The Transfluor assay employs a a beta-arrestin-GFP fusion protein to detect activation of GPCRs: Upon ligand binding the GPCR, cytosolic arrestin-GFP quickly translocates to the cell membrane and then to endocytic vesicles, where it 'clusters' and can be detected by fluorescent image analysis. (Developed / commercialized by Norak, then Molecular Devices)
subclass of: BAO_0000110

perturbagen / positive control ratio endpoint
type: Class
IAO_0000115: The property values are divided by the average value for the positive control wells and multiplied by 100: X' = 100*(X/PosAvg)
IAO_0000118: percent postive control
IAO_0000118: % positive control
subclass of: percent control

Relative Induction Score
type: Class
IAO_0000118: RIS
subclass of: physical property endpoint
submitted by: SEED Project - Pistoia Alliance
IAO_0000118: Relative Induction Score (RIS)

Emax
type: Class
subclass of: graphical calculation endpoint
IAO_0000115: Maximum induction effect (dimensionless)

molar attenuation coefficient
type: Class
subclass of: physical property endpoint
IAO_0000115: This is a measurement of how strongly a chemical species attenuates light at a given wavelength. Common units are L/(mol*cm).

max fold increase
type: Class
subclass of: fold change
IAO_0000115: The maximum observed fold increase.

fraction unbound
type: Class
subclass of: physical property endpoint
IAO_0000115: The fraction of compound that does not bind to substrate (e.x. plasma proteins)

cell count
type: Class
subclass of: raw activity
IAO_0000115: Count of cells as an endpoint

ratio endpoint
type: Class
subclass of: endpoint
IAO_0000115: A ratio endpoint is the relative relation between two quantitative results (a/b)

blood to plasma ratio
type: Class
subclass of: ratio endpoint
IAO_0000115: The ratio of the concentration of molecule in whole blood (i.e. contains both red blood cells and plasma) to the concentration of molecule in plasma, namely CB/CP.

AC50 Ratio
type: Class
IAO_0000115: Ratio of AC50 values
subclass of: ratio endpoint
subclass of: concentration response endpoint

categorical endpoint
type: Class
subclass of: endpoint
IAO_0000115: A categorical endpoint is any result that can take one of a limited number of possible values.

electrical endpoint
type: Class
subclass of: endpoint
IAO_0000115: Branch of endpoints reported by electrical measurements.
submitted by: https://github.com/Scientist328455 https://github.com/BioAssayOntology/BAO/issues/62

electrical current density
type: Class
subclass of: electrical endpoint
IAO_0000115: Electrical current density is a measure of the density of flow of electric charge; it is the electric current per unit area of cross section. Electric current density is a vector-valued quantity.
has xref: https://qudt.org/vocab/quantitykind/ElectricCurrentDensity
submitted by: https://github.com/Scientist328455 https://github.com/BioAssayOntology/BAO/issues/62

fraction metabolised
type: Class
subclass of: physical property endpoint
IAO_0000115: The fraction of the bioavailable dose which has been metabolized.
has xref: http://ncicb.nci.nih.gov/xml/owl/EVS/Thesaurus.owl#C184704
submitted by: SEED Project - Pistoia Alliance

Kp
type: Class
subclass of: ratio endpoint
IAO_0000115: Kp values are defined as the ratio of total concentration of compound in the tissue to total concentration of compound in the plasma at steady state.
has xref: https://github.com/BioAssayOntology/BAO/issues/103
submitted by: https://github.com/Scientist328455
IAO_0000118: tissue-to-plasma concentration ratio

kobs
type: Class
subclass of: enzyme kinetic constant
IAO_0000115: observed rate constant
submitted by: https://github.com/Scientist328455

physiological endpoint
type: Class
IAO_0000115: A physiological endpoint is a response from either an isolated tissue or organ (i.e. smooth muscle contraction, urine output ) that also serves as an observed enpoint for a bioassay.
subclass of: endpoint
submitted by: Opioid Drug Ontology (ODO) (https://opioiddrugontology.github.io/) - Nicolette Ross (https://orcid.org/0000-0002-4677-2140)
IAO_0000116: [DefinitionUpdate: BAO v 2.8.15 (May 2025)] [NodeCreation: BAO v 2.8.13 (March 2025)]

urine output
type: Class
IAO_0000115: The amount of urine excreted.
subclass of: physiological endpoint
submitted by: Opioid Drug Ontology (ODO) (https://opioiddrugontology.github.io/) - Nicolette Ross (https://orcid.org/0000-0002-4677-2140)
IAO_0000116: [DefinitionUpdate: BAO v 2.8.15 (May 2025)] [NodeCreation: BAO v 2.8.13 (March 2025)]

relative bias
type: Class
IAO_0000115: Ratio of functional bias calculated for a test agonist compound/the measured functional bias of a reference agonist compound allowing for normalization within a single assay (parameter: ΔLog τ/KA).
subclass of: ratio endpoint
submitted by: Opioid Drug Ontology (ODO) (https://opioiddrugontology.github.io/) - Nicolette Ross (https://orcid.org/0000-0002-4677-2140)
IAO_0000116: [DefinitionUpdate: BAO v 2.8.15 (May 2025)] [NodeCreation: BAO v 2.8.13 (March 2025)]

bias factor
type: Class
IAO_0000115: The bias factor, defined as 10ˆΔΔLogτ/KA(assay1-assay2), quantifies the difference in relative agonist activity between two assays. A higher bias factor indicates a greater distinction in the agonist's performance across the two assays relative to the reference agonist.
subclass of: ratio endpoint
submitted by: Opioid Drug Ontology (ODO) (https://opioiddrugontology.github.io/) - Nicolette Ross (https://orcid.org/0000-0002-4677-2140)
IAO_0000119: https://doi.org/10.1016/j.cell.2017.10.035
IAO_0000116: [DefinitionUpdate: BAO v 2.8.15 (May 2025)] [NodeCreation: BAO v 2.8.13 (March 2025)]