1. What is Michaelis Constant?

Definition: The Michaelis Constant (K_M) is numerically equal to the substrate concentration at which the reaction rate is half of the maximum rate of the system.

Purpose: It's a key parameter in enzyme kinetics that indicates the affinity of an enzyme for its substrate.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( K_M \) — Michaelis Constant (mol/m³)
• \( V_{max} \) — Maximum reaction rate (mol/m³·s)
• \( [S] \) — Substrate concentration (mol/m³)
• \( V_0 \) — Initial reaction rate (mol/m³·s)

Explanation: This formula calculates K_M from measurable kinetic parameters at low substrate concentrations.

3. Importance of Michaelis Constant

Details: K_M is crucial for understanding enzyme efficiency, designing experiments, and predicting enzyme behavior under different conditions.

4. Using the Calculator

Tips: Enter the maximum rate (V_max), substrate concentration ([S]), and initial reaction rate (V₀). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What does a low K_M value indicate?
A: A low K_M indicates high enzyme-substrate affinity, meaning the enzyme reaches half its maximum velocity at low substrate concentrations.

Q2: How is V_max determined experimentally?
A: V_max is determined by measuring reaction rates at increasing substrate concentrations until the rate plateaus.

Q3: What units should I use for inputs?
A: The calculator uses mol/m³·s for rates and mol/m³ for concentrations, but any consistent unit system will work.

Q4: Can this calculator be used for inhibitor studies?
A: Yes, but be aware that different inhibitor types affect K_M and V_max differently.

Q5: What's a typical range for K_M values?
A: K_M values vary widely but typically range from 10^-6 to 10^-2 M for most enzymes.