Initial Enzyme Concentration given Dissociation Rate Constant Calculator

Formula Used:

\[ [E_{initial}] = \frac{[ES] \times (K_D + [S])}{[S]} \]

Enzyme Substrate Complex Concentration:

mol/m³

Dissociation Rate Constant:

mol/m³

Substrate Concentration:

mol/m³

Initial Enzyme Concentration (mol/m³):

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1. What is Initial Enzyme Concentration given Dissociation Rate Constant?

Definition: This calculator determines the initial concentration of enzyme based on the enzyme-substrate complex concentration, dissociation rate constant, and substrate concentration.

Purpose: It helps biochemists and researchers understand enzyme kinetics and quantify enzyme concentrations in reaction systems.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ [E_{initial}] = \frac{[ES] \times (K_D + [S])}{[S]} \]

Where:

\( [E_{initial}] \) — Initial enzyme concentration (mol/m³)
\( [ES] \) — Enzyme-substrate complex concentration (mol/m³)
\( K_D \) — Dissociation rate constant (mol/m³)
\( [S] \) — Substrate concentration (mol/m³)

Explanation: The formula calculates the total enzyme concentration by accounting for both free enzyme and enzyme bound in the ES complex.

3. Importance of Initial Enzyme Concentration

Details: Knowing the initial enzyme concentration is crucial for determining reaction rates, enzyme efficiency (kcat/Km), and understanding enzyme inhibition mechanisms.

4. Using the Calculator

Tips: Enter the enzyme-substrate complex concentration, dissociation rate constant, and substrate concentration. All values must be positive (except KD which can be zero).

5. Frequently Asked Questions (FAQ)

Q1: What is the dissociation rate constant (KD)?
A: KD is the equilibrium constant for the dissociation of the enzyme-substrate complex into free enzyme and substrate.

Q2: How do I measure enzyme-substrate complex concentration?
A: ES complex can be measured using spectroscopic methods, rapid-quench techniques, or other kinetic assays.

Q3: What units should I use for the inputs?
A: The calculator uses mol/m³ for all concentrations, but you can convert from other units (e.g., mM to mol/m³ by multiplying by 1000).

Q4: Can KD be zero?
A: Yes, if the enzyme-substrate complex doesn't dissociate, KD would be zero (irreversible binding).

Q5: How does this relate to Michaelis-Menten kinetics?
A: This calculation is fundamental to understanding the relationship between enzyme, substrate, and ES complex in Michaelis-Menten kinetics.