1. What is Reverse Rate Constant in Enzymatic Reactions?

Definition: The reverse rate constant (k_r) quantifies the rate at which the enzyme-substrate complex dissociates back into free enzyme and substrate.

Purpose: This calculator helps biochemists and enzymologists determine the reverse rate constant in Michaelis-Menten kinetics.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( k_r \) — Reverse rate constant (mol/m³·s)
• \( k_f \) — Forward rate constant (1/s)
• \( S \) — Substrate concentration (mol/m³)
• \( [E_0] \) — Initial enzyme concentration (mol/m³)
• \( ES \) — Enzyme-substrate complex concentration (mol/m³)

Explanation: The formula calculates how quickly the enzyme-substrate complex breaks down based on reaction parameters.

3. Importance of Reverse Rate Constant

Details: Understanding k_r is crucial for modeling enzyme kinetics, determining reaction equilibrium, and designing enzyme inhibitors.

4. Using the Calculator

Tips: Enter all positive values with [E₀] > ES. Typical units shown, but ensure consistency in your measurements.

5. Frequently Asked Questions (FAQ)

Q1: What's the relationship between k_r and enzyme efficiency?
A: Lower k_r values generally indicate more stable enzyme-substrate complexes and potentially more efficient catalysis.

Q2: How do I measure the forward rate constant (k_f)?
A: k_f is typically determined experimentally using stopped-flow techniques or other rapid kinetic methods.

Q3: What if my [E₀] is less than ES?
A: This is impossible physically - check your measurements as ES cannot exceed [E₀].

Q4: How does temperature affect k_r?
A: Like most rate constants, k_r typically increases with temperature following Arrhenius equation behavior.

Q5: Can I use this for non-enzymatic reactions?
A: The formula applies to any reversible reaction following similar kinetics, not just enzymatic ones.