# Enzyme Kinetics Calculator (Michaelis-Menten) Calculate reaction velocity with Michaelis-Menten, estimate Km/Vmax via Lineweaver-Burk, and model enzyme inhibition. > Canonical page: https://elysiatools.com/en/tools/enzyme-kinetics-calculator - **Category:** Math & Numbers - **Keywords:** enzyme kinetics, michaelis-menten, km, vmax, lineweaver-burk, biochemistry ## Overview The Enzyme Kinetics Calculator helps biochemists and researchers analyze enzymatic reactions by calculating reaction velocity using the Michaelis-Menten equation or estimating Km and Vmax from experimental data via Lineweaver-Burk plots. It also supports modeling competitive, uncompetitive, and non-competitive enzyme inhibition to evaluate the impact of inhibitors on reaction rates. ## Inputs - **Calculation Mode** (select) - **Max Velocity Vmax (mol/L·s)** (number): Maximum reaction velocity at saturating substrate. - **Michaelis Constant Km (mol/L)** (number): Substrate concentration at half-maximal velocity. - **Substrate Concentration \[S\] (mol/L)** (number): e.g. 0.5 - **Substrate-Velocity Data (S, v) pairs** (textarea): Used in 'Find Km & Vmax' mode. At least 2 pairs, both > 0. - **Inhibition Type** (select) - **Inhibitor Concentration \[I\] (mol/L)** (number): e.g. 0.1 - **Inhibition Constant Ki (mol/L)** (number): e.g. 0.05 - **Decimal Places** (number) ## When to use - When you need to calculate the initial reaction velocity of an enzyme-catalyzed reaction at a specific substrate concentration. - When you have experimental substrate-velocity data pairs and want to determine the kinetic parameters Km and Vmax using a Lineweaver-Burk double-reciprocal fit. - When modeling the effects of competitive, uncompetitive, or non-competitive inhibitors on enzyme kinetics with known inhibitor concentrations and Ki values. ## How it works - Select the calculation mode: either calculate reaction velocity (v) or fit experimental data to find Km and Vmax. - Input the required kinetic parameters such as Vmax, Km, and substrate concentration, or paste your raw substrate-velocity (S, v) data pairs. - Optionally configure inhibition parameters by choosing the inhibition type (competitive, uncompetitive, or non-competitive) and entering the inhibitor concentration and Ki. - Click calculate to generate the JSON output containing the calculated velocity, apparent kinetic constants, and fitting metrics. ## Use cases - Determining the Km and Vmax of a newly isolated enzyme from laboratory assay data. - Simulating the reduction in reaction velocity when a competitive inhibitor is introduced at varying concentrations. - Verifying theoretical Michaelis-Menten reaction rates for biochemistry homework or lecture demonstrations. ## Frequently asked questions ### What is the difference between the two calculation modes? The velocity mode calculates the reaction rate (v) using known Km, Vmax, and substrate values, while the fit mode estimates Km and Vmax from experimental substrate-velocity data pairs using a Lineweaver-Burk linear regression. ### How should I format the experimental data pairs in fit mode? Enter each pair on a new line or separated by spaces in the format 'Substrate,Velocity' (e.g., '0.1,0.2'). You must provide at least two pairs with values greater than zero. ### Which types of enzyme inhibition can this calculator model? It supports competitive (increases apparent Km), uncompetitive (decreases both Km and Vmax), and non-competitive (decreases Vmax only) inhibition models. ### What units should I use for the concentrations and velocities? You can use any consistent concentration units (such as mol/L or M) and velocity units (such as mol/L·s), as long as they match across all input fields. ### How does the calculator handle the Lineweaver-Burk fit? It takes the reciprocal of your substrate and velocity data points, performs a linear regression to find the slope and y-intercept, and derives Km and Vmax from those values. ## Related tools - [Absolute Value Calculator](https://elysiatools.com/en/tools/absolute-value-calculator): Calculate the absolute value of positive, negative, or decimal numbers and explain the sign relationship - [Adjusted R-Squared Calculator](https://elysiatools.com/en/tools/adjusted-r-squared-calculator): Calculate adjusted R squared from R squared, sample size, and predictor count - [Air Changes per Hour (ACH, n = Q/V)](https://elysiatools.com/en/tools/air-changes-per-hour): Compute the air change rate (ACH / n) of a room from the outdoor supply airflow Q and the room volume V: n = Q/V (1/h). Three modes: solve ACH (given Q and V), solve airflow (given n and V), or solve volume (given n and Q). Flow in m³/s/m³/h/CFM, volume in m³/ft³/L. 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