Enzyme Activity and Kinetics Assay Development
Custom Enzyme Activity and Kinetics Assays Built Around Your Enzyme
We develop and validate biochemical assays that measure catalytic activity and derive kinetic parameters such as Vmax, Km, kcat, and kcat/Km for your enzyme and substrate of interest.
What This Service Delivers
Enzyme activity assays measure the catalytic rate of an enzyme by monitoring substrate consumption or product formation over time under defined conditions of pH, temperature, and buffer. Kinetic assays extend this by measuring initial reaction rates across a range of substrate concentrations, allowing parameters such as Vmax, Km, kcat, and kcat/Km to be derived through Michaelis-Menten analysis.
For enzyme discovery teams and academic spinouts, this matters because potency, selectivity, and mechanism-of-action data are what separate a promising candidate from a dead end. Our service develops and validates custom assays around your specific enzyme and substrate, so the numbers you use for lead selection reflect the chemistry you actually care about rather than a generic kit readout.
Enzyme Activity Measurement
We establish a working activity assay for your enzyme by defining reaction conditions and a detection mode that reports substrate consumption or product formation reliably.
- Evaluation of enzyme activity under defined pH, temperature, and buffer conditions
- Blank and control samples to account for non-enzymatic background
- Detection approaches selected to suit the enzyme and substrate pair
Kinetic Parameter Determination
Initial rate measurements across a substrate concentration series are fitted to derive the kinetic constants that describe your enzyme's behavior.
- Substrate concentration-response curves and initial rate measurements
- Derivation of Vmax, Km, kcat, and kcat/Km
- Additional parameters such as Kd, ka, and kb where the assay design supports them
Inhibitor and Selectivity Testing
The same assay framework is used to evaluate how compounds modulate your enzyme, supporting potency ranking and selectivity assessment.
- Determination of enzyme inhibitors and IC50 values
- Investigation of enzyme selectivity across related targets or substrates
- Mechanism-of-action information to support lead optimization
Assay Formats and Readouts
Enzyme kinetic assays can be built on several detection principles, and the right choice depends on your enzyme, your substrate, and the sensitivity your decision requires. Commonly used formats include spectrophotometric and colorimetric readouts, fluorometric detection, luminescence, chromatographic separation with HPLC or TLC, and continuous monitoring approaches for real-time rate measurement.
Assay development is a design exercise, not a catalog pick. We work with you to select a format that reports the chemistry of interest with adequate signal and low background, then confirm it performs consistently before it is used for kinetic or inhibitor work.
| Assay Format | Detection Principle | Typical Fit | Considerations |
|---|---|---|---|
| Spectrophotometric / colorimetric | Change in absorbance as substrate is consumed or a colored product forms | Widely used for enzymes with chromogenic substrates or coupled readouts | Requires a measurable absorbance change at a defined wavelength |
| Fluorometric | Fluorescent product or substrate measured on a fluorescence reader | Suited to enzymes that generate or consume fluorescent species | Sensitive, but sensitive to inner-filter and quenching effects |
| Luminescence | Light emission resulting from the enzymatic reaction | Useful where a luminescent reporter chemistry is available | Signal stability and background must be characterized |
| Chromatographic (HPLC / TLC) | Separation of reaction components with quantification of product or substrate | Valuable when substrate and product are not optically distinguishable | Throughput is lower than plate-based optical formats |
How Engagement Works
Every project starts from your enzyme, your substrate, and the decision the data needs to support. The workflow below describes the sequence we follow; the depth at each stage is defined in the project scope.
Scope and Feasibility Review
We review your enzyme, substrate, sample matrix, and the kinetic or inhibition questions you need answered, then agree on the assay concept and the parameters to be reported.
Assay Design and Reagent Setup
Enzyme solution, substrate solution, and buffer are prepared at the intended experimental concentrations and pH, with blank and control samples defined to establish baseline reaction behavior.
Reaction and Rate Measurement
Reaction components are combined and the change in the chosen detection signal is monitored over a defined time window to capture the initial rate of the enzyme-catalyzed reaction.
Data Analysis and Parameter Fitting
Initial rates are plotted against substrate concentration and fitted to the Michaelis-Menten relationship to derive Vmax, Km, and related constants, with inhibitor data analyzed for IC50 and mode of action.
What Can Be Customized
Assay conditions, detection strategy, and validation depth are defined case by case after consultation, because the right design depends on the enzyme and the substrate rather than on a fixed menu.
Reaction Condition Optimization
Buffer composition, pH, temperature, and ionic conditions are adjusted to place the enzyme in a well-behaved regime before kinetic work begins.
- Assay optimization for pH, temperature, and buffer conditions
- Substrate concentration ranges selected around the expected Km
- Control and blank design to isolate specific from non-specific signal
Substrate and Matrix Flexibility
Assays can be developed for defined substrates, including specialized chemistries, and for enzymes supplied as purified protein or in a biological matrix.
- Purified or recombinant enzyme preparations
- Cell lysate and plasma-type biological samples
- Substrate concentration-response curves tailored to the target chemistry
Validation and Documentation
Validation depth is scoped to the intended use of the data, from fit-for-purpose confirmation through to documentation aligned with your regulatory requirements.
- QC validation and regulatory compliance considerations
- Linearity with protein content and reaction time
- Deliverable: validated assay protocol and supporting data
Service Scope
The table below describes the parameters that can be customized for your project. Specific values, sample numbers, and validation depth are agreed in the project scope after consultation.
| Parameter | Typical Project Scope | What You Receive | Notes |
|---|---|---|---|
| Enzyme system | Purified enzyme, recombinant enzyme preparation, cell lysate, or plasma-type sample | Assay conditions matched to the supplied material | Matrix effects characterized during development |
| Detection format | Spectrophotometric, colorimetric, fluorometric, luminescent, or chromatographic readout | Selected readout with documented signal and background behavior | Format chosen to suit the enzyme-substrate pair |
| Kinetic parameters | Vmax, Km, kcat, kcat/Km, and where supported Kd, ka, kb | Fitted parameter values with curve data | Requires a workable substrate concentration series |
| Inhibitor testing | Inhibitor titration and IC50 determination, selectivity across related targets | Potency and selectivity data to support lead ranking | Compound series and concentration ranges scoped per project |
| Assay optimization | pH, temperature, buffer, and substrate range optimization | Documented optimized conditions | Iterative, based on observed assay performance |
| Validation depth | Fit-for-purpose confirmation through to documentation aligned with regulatory requirements | Validated assay protocol and data package | Scope agreed against the intended use of the data |
Sample and Data Requirements
Assay development moves fastest when the enzyme, substrate, and reference compounds arrive with enough information to design the first experiment. The table summarizes what is typically needed to start and what is returned at the end of a project.
| Item | Purpose | Notes | |
|---|---|---|---|
| Enzyme material | Client | Defines the catalytic system under study | Purified, recombinant, or matrix-associated forms can be discussed |
| Substrate and reference compounds | Client or agreed sourcing | Enables substrate concentration-response and inhibitor testing | Solubility and stability considerations reviewed at scoping |
| Background information | Client | Informs buffer, pH, and detection strategy | Known cofactors, expected Km range, and prior data are helpful |
| Validated assay protocol and data | Our team | Deliverable for downstream decision-making | Includes fitted parameters and supporting curves |
Why Teams Use This Service
Enzyme activity and kinetics data sit at the center of lead selection, but building a reliable assay in-house competes with the discovery work it is meant to support. Working with a dedicated assay development team keeps that effort focused and reproducible.
Our scientists develop and validate customized assays for a range of enzymes, working closely with clients so the design meets their specific needs and regulatory requirements.
Built Around Your Enzyme
Assays are designed for the enzyme and substrate you are developing, not adapted from a generic kit with fixed chemistry.
- Substrate ranges and detection modes matched to your system
- Conditions optimized before kinetic parameters are reported
- Inhibitor and selectivity work performed on the same validated assay
Data for Lead Selection
The output is intended to support potency ranking, selectivity assessment, and mechanism-of-action understanding during candidate selection.
- Kinetic constants that describe affinity and catalytic efficiency
- IC50 and selectivity data across compound series
- Mechanistic information to distinguish inhibitor classes
Documented and Reproducible
Assay performance is characterized before results are reported, and the validated protocol is handed over so the method can be understood and reused.
- Blank and control samples used to establish baseline behavior
- Linearity checks with protein content and reaction time
- Validated assay protocol delivered with the data package
Applications We Support
Enzyme activity and kinetic assays are used across drug discovery, diagnostics development, and enzyme engineering programs. Typical applications include evaluating the potency, selectivity, and mechanism of action of drug candidates, characterizing engineered enzyme variants, and supporting functional assessment of enzymes relevant to diagnostic or therapeutic use.
Because assay design is driven by the enzyme and substrate rather than by a fixed panel, the same development framework can be applied to a range of target chemistries, including specialized substrates where a suitable detection strategy can be established.
Getting Started
Share your enzyme, substrate, sample matrix, and the kinetic or inhibition questions you need answered. We will review feasibility, propose an assay concept, and outline the parameters and validation depth that fit your intended use.
From there, the project scope defines the conditions to be optimized, the parameters to be reported, and the format of the final validated assay protocol and data package.
FAQ
What is the difference between an enzyme activity assay and a kinetic assay?
An activity assay measures the catalytic rate of an enzyme by monitoring substrate consumption or product formation over time under defined conditions. A kinetic assay extends this by measuring initial reaction rates at multiple substrate concentrations, which allows parameters such as Vmax, Km, kcat, and kcat/Km to be derived through Michaelis-Menten analysis. In practice, the activity assay is the foundation, and the kinetic work builds on it once conditions are established.
Which kinetic parameters can you determine for my enzyme?
Depending on the assay design and the substrate concentration range that can be achieved, we can derive Vmax, Km, kcat, and kcat/Km, and where the assay supports it, additional parameters such as Kd, ka, and kb. The feasible parameter set is discussed during scoping, because it depends on the enzyme, the substrate, and the detection strategy rather than on a fixed list.
Can you test inhibitors and assess selectivity with the same assay?
Yes. The same validated assay framework is commonly used to determine enzyme inhibitors and IC50 values and to investigate enzyme selectivity across related targets or substrates. Mechanism-of-action information can also be extracted from inhibitor experiments, which is useful for classifying compounds and supporting lead optimization decisions.
What sample types can be used for assay development?
Assays can be developed for purified enzymes, recombinant enzyme preparations, cell lysates, and plasma-type biological samples. The sample matrix affects background signal and detection choice, so matrix behavior is characterized during development. If you are unsure whether your material is suitable, that is assessed during the feasibility review before the project scope is finalized.
What do we receive at the end of the project?
The deliverable is a validated assay protocol together with the supporting data package, including the fitted kinetic parameters and the underlying curve data. Validation depth is scoped to the intended use of the data, ranging from fit-for-purpose confirmation through to documentation aligned with your regulatory requirements, and the agreed scope is confirmed before work begins.
References
- Schweipert M, Amurthavasan A, Meyer-Almes FJ. Continuous enzyme activity assay for high-throughput classification of histone deacetylase 8 inhibitors. Exploration of targeted anti-tumor therapy. 2023;4(3):447-459. View on PubMed
- Ruan Y, Zhu X, Shen J, et al. Mechanism of Nicotiflorin in San-Ye-Qing rhizome for anti-inflammatory effect in ulcerative colitis. Phytomedicine: international journal of phytotherapy and phytopharmacology. 2024;129:155564. View on PubMed
- Russ E, Ziemons J, Hillege LE, et al. Evaluation of potential biomarkers during irinotecan-based systemic treatment for colorectal cancer-study protocol of the OPTIMA study. BMC cancer. 2025;25(1):1129. View on PubMed
- Trinidad M, Hong X, Froelich S, et al. Predicting disease severity in metachromatic leukodystrophy using protein activity and a patient phenotype matrix. Genome biology. 2023;24(1):172. View on PubMed
- Meng Q, Novak A, Rayhill E. Zymography: Unveiling Matrix Metalloproteinase Dynamics. Methods in molecular biology (Clifton, N.J.). 2025;2917:57-64. View on PubMed
Discuss Your Enzyme Assay Project
Send us your enzyme, substrate, and the kinetic or inhibition questions you need answered. We will review feasibility and outline an assay development plan scoped to your intended use.