Enzymology Services
Enzymatic Activity Assay Services
Quantify how compounds inhibit target enzymes such as human maltase-glucoamylase with defined, validated activity assays.
What This Service Measures
An enzymatic activity assay measures the catalytic function of an enzyme by monitoring conversion of a specific substrate to product under defined conditions. Rather than reporting protein abundance, it reports turnover — the functional readout that matters when you are ranking inhibitors, confirming mechanism of action, or comparing compound potency across a series.
For inhibitor programs, the effect of a test compound is quantified by comparing reaction rates in the presence and absence of the inhibitor. This supports hit identification and lead optimization for targets such as human maltase-glucoamylase, where quantitative activity data underpin decisions about which compounds to advance.
Enzyme Target and Source
Projects begin by defining the enzyme target, its source, and the supply plan for active protein.
- Purified enzyme or enzyme in a biological matrix such as cell lysate or tissue homogenate
- Documented source, purity, and activity expectations
- Target-family experience applied to assay design choices
Substrate and Readout
The substrate and detection method are selected so that turnover produces a measurable, interference-aware signal.
- Absorbance, fluorescence, or luminescence readouts
- Continuous or endpoint detection depending on the question
- Interference risks and controls considered during selection
Assay Conditions and Optimization
Buffer, pH, temperature, cofactors, and incubation time are optimized for the specific enzyme-substrate pair.
- Enzyme concentration and linear range determined experimentally
- Substrate concentration set near or below Km
- Positive and negative controls included in every run
| Parameter | Typical project scope | How it is defined | Why it matters |
|---|---|---|---|
| Enzyme target and source | Purified enzyme or defined biological matrix | Confirmed with client at project start | Determines feasibility of the readout and control strategy |
| Substrate and detection method | Absorbance, fluorescence, or luminescence | Selected for signal window and interference profile | Sets sensitivity and compatibility with compound libraries |
| Reaction conditions | Reaction conditions such as pH, temperature, buffer, cofactors, and incubation time are optimized for each enzyme-substrate pair. | Optimized per enzyme-substrate pair | Ensures the measured rate reflects catalytic activity |
| Enzyme concentration and linear range | Titrated to initial-velocity conditions | Determined experimentally before screening | Prevents enzyme-concentration artifacts in inhibition data |
| Substrate concentration | Near or below Km | Set relative to the measured Km | Keeps the assay sensitive to competitive inhibition |
| Controls and reference inhibitors | Positive and negative controls per plate | Included in every run with defined plate maps | Supports data quality assessment and false-positive reduction |
| Data analysis | Initial rates and inhibition parameters | Calculated with models appropriate to the inhibition mode | Avoids incorrect inhibition constants from improper models |
| Assay validation | Z′ and signal-to-background assessment | Evaluated under final screening conditions | Indicates whether the assay is suitable for screening scale |
How Engagement Works
Each project follows a defined path from target definition to a validated assay and analyzed data, with review points where scope and acceptance criteria are confirmed.
Define target and screening goals
We confirm the enzyme target, its source, the biological question, and whether the goal is primary screening, profiling, or hit-to-lead triage.
Select substrate and detection method
Substrate and readout are chosen for signal window, sensitivity, and compatibility with your compound set, with interference risks noted.
Optimize reaction conditions
Buffer, pH, temperature, cofactors, and incubation time are adjusted for the specific enzyme-substrate pair, and enzyme concentration is titrated to establish the linear range.
Run controls and reference inhibitors
Positive and negative controls and reference inhibitors are included so that compound effects can be interpreted against a defined baseline.
Customization Options
Assay scope is defined case by case after consultation, because the right configuration depends on your enzyme, substrate, compound set, and decision point.
The options below describe what can be tailored; the final scope, controls, and validation depth are agreed in the project plan.
Detection Format
Readout is matched to the enzyme and the question, from continuous kinetic monitoring to endpoint measurement.
- Absorbance, fluorescence, or luminescence
- Continuous detection for residence-time style questions
- Alternative readouts considered when interference is a risk
Plate Format and Scale
Plate format and reagent volumes are scoped to the number of compounds and the throughput you need.
- Low-volume formats for compound-sparing work
- Plate maps and control layouts defined per project
- Miniaturization considered where it preserves signal quality
Inhibition Characterization
Beyond single-point inhibition, assays can be configured to characterize how compounds affect enzyme kinetics.
- Dose-response and IC50-style comparisons
- Inhibition constant determination with appropriate models
- Mechanism-of-action follow-up for confirmed actives
Deliverables and Data Package
Deliverables are defined in the project plan and typically include the analyzed dataset, the methods used, and the documentation needed to interpret or transfer the assay.
The table below outlines the deliverable categories and what each contains.
| Deliverable | Contents | Format | Notes |
|---|---|---|---|
| Analyzed activity data | Initial rates and inhibition parameters for tested compounds | Tabulated dataset | Calculated with models appropriate to the inhibition mode |
| Assay methods summary | Enzyme source, substrate, buffer, pH, temperature, and detection settings | Written methods description | Supports reproducibility and method documentation |
| Control and validation results | Positive and negative control performance, Z′ and signal-to-background | Summary tables or figures | Assessed under final assay conditions |
| Plate maps and acceptance criteria | Control positions and criteria used to accept or repeat runs | Documentation | Useful when transferring the assay to another site |
| Raw data | Instrument-level readings underlying the analysis | Electronic files | Provided with the analyzed dataset |
| Project report | Findings, observations, and any assay limitations noted during the work | Written report | Reviewed with you at project milestones |
Why Teams Choose This Approach
Enzymatic activity data is only useful if the assay behind it is well controlled. We focus on the parameters that determine whether inhibition numbers can be trusted and compared across a compound series.
The differentiators below reflect how projects are typically structured and reviewed.
Conditions Set by Experiment
Enzyme concentration, linear range, and substrate level are established experimentally rather than assumed.
- Initial-velocity conditions confirmed before screening
- Substrate near or below Km for inhibitor sensitivity
- Enzyme-concentration artifacts explicitly checked
Controls Built Into Every Run
Positive and negative controls and reference inhibitors are part of the standard plate layout.
- Defined plate maps and acceptance criteria
- Z′ and signal-to-background assessed under final conditions
- Interference risks considered during readout selection
Analysis Fit to the Question
Data analysis is matched to the inhibition mode rather than applying a single default model.
- Initial rates calculated from the linear portion of the reaction
- Inhibition constants determined with appropriate models
- Mechanism follow-up available for confirmed actives
| Element | Typical project scope | Notes | |
|---|---|---|---|
| Enzyme target and source | Purified enzyme or defined biological matrix | Project start | Source and activity expectations documented |
| Substrate and detection method | Absorbance, fluorescence, or luminescence | Assay design | Selected for signal window and interference profile |
| Reaction conditions | Reaction conditions such as pH, temperature, buffer, cofactors, and incubation time are optimized for each enzyme-substrate pair. | Assay optimization | Optimized per enzyme-substrate pair |
| Controls and reference inhibitors | Positive and negative controls per plate | Assay design | Included in every run with defined plate maps |
| Data analysis | Initial rates and inhibition parameters | Reporting | Models matched to the inhibition mode |
| Assay validation | Z′ and signal-to-background assessment | Before screening scale | Evaluated under final assay conditions |
| Technical support | A named scientific contact is assigned at project start, milestone review calls are scheduled, and email inquiries receive a response within 1 business day. | Project start | Consistent across projects |
Assay Validation and Quality
Assay validation confirms that the readout is stable enough to support the decisions you plan to make with it. Under final screening conditions, we assess signal window, plate-to-plate reproducibility, and control performance, and we report Z′ and signal-to-background alongside the compound data.
Controls are chosen to reduce false positives — for example, detergent controls for aggregators and enzyme titrations to confirm that inhibition is not an artifact of enzyme concentration. Where an active compound is confirmed, orthogonal or biophysical follow-up can be discussed as part of the project scope.
FAQ
What should I include in a brief for an enzymatic activity assay project?
A useful brief covers target biology, enzyme source and quality, substrates and cofactors, the desired readout, expected throughput, known inhibitors or activators, and any interference risks. It also helps to state the decision the data must support — primary screening, profiling, or hit-to-lead triage — because that shapes assay design and validation depth.
How do I know the assay is suitable for screening scale?
Look for a stable signal window, plate-to-plate reproducibility, and defined controls and plate maps under final screening conditions. Z′ is commonly used as an indicator, with values in the range of roughly 0.6 to 0.7 often cited as a practical benchmark for HTS-ready assays. We report the values measured in your project rather than assuming a universal threshold.
When is a custom assay needed instead of a standard format?
A custom design is typically needed when the reaction product is not detectable with a robust standard method, or when the biology requires mechanism-specific detection or kinetics that a standard format cannot capture. In those cases, assay design focuses on substrate choice, detection strategy, and control layout specific to your enzyme.
What controls help reduce false positives in inhibition assays?
Common controls include detergent controls for aggregators, enzyme titrations to confirm that inhibition is not an enzyme-concentration artifact, and alternative or red-shifted readouts. For confirmed actives, orthogonal or biophysical confirmation can be added. The exact control set is agreed during scoping based on your compound series and target.
Can the assay be transferred to our own lab or screening group?
Yes, transfer support can be included in scope. Typical transfer materials include SOPs, raw data, plate layouts, acceptance criteria, and a pilot run with the receiving team. This documentation is prepared so that your group can reproduce the assay under the conditions validated during the project.
References
- Smirnovienė J, Baranauskienė L, Zubrienė A, et al. A standard operating procedure for an enzymatic activity inhibition assay. European biophysics journal: EBJ. 2021;50(3-4):345-352. View on PubMed
- Gaspar P, Marques ARA, Ferraz MJ, et al. LIMP-2 deficiency-associated glycolipid abnormalities in mice. Biochimica et biophysica acta. Molecular and cell biology of lipids. 2025;1870(7):159657. View on PubMed
- Zhou H, Wu Z, Wang Y, et al. Rare Diseases in Glycosphingolipid Metabolism. Advances in experimental medicine and biology. 2022;1372:189-213. View on PubMed
- Wei J, Yan T, Liang Y. Targeting TRAF3IP2 alleviates high glucose-induced cardiomyocyte inflammation and apoptosis. Drug development research. 2022;83(1):167-175. 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
Discuss your enzyme inhibition project
Share your target, substrate, and compound set, and we will propose an assay design, control strategy, and validation approach for your review.