Initial Enzyme Concentration given Catalytic Rate Constant and Dissociation Rate Constants Calculator

Formula Used:

\[ [E_0] = \frac{V_0 \times (K_D + S)}{k_{cat} \times S} \]

Initial Reaction Rate (V₀):

mol/m³·s

Dissociation Rate Constant (K_D):

mol/m³

Substrate Concentration (S):

mol/m³

Catalytic Rate Constant (k_cat):

s⁻¹

Initial Enzyme Concentration [E₀]: mol/m³

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Initial Enzyme Concentration?

Definition: The Initial Enzyme Concentration is defined as the concentration of enzyme at the start of the reaction.

Purpose: This calculator helps biochemists and researchers determine the required enzyme concentration for their experiments based on reaction kinetics.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ [E_0] = \frac{V_0 \times (K_D + S)}{k_{cat} \times S} \]

Where:

\( [E_0] \) — Initial enzyme concentration (mol/m³)
\( V_0 \) — Initial reaction rate (mol/m³·s)
\( K_D \) — Dissociation rate constant (mol/m³)
\( S \) — Substrate concentration (mol/m³)
\( k_{cat} \) — Catalytic rate constant (s⁻¹)

Explanation: The formula calculates the enzyme concentration needed to achieve a specific initial reaction rate given the substrate concentration and kinetic constants.

3. Importance of Enzyme Concentration Calculation

Details: Accurate enzyme concentration is crucial for experimental design, ensuring proper reaction rates and meaningful kinetic studies.

4. Using the Calculator

Tips: Enter the initial reaction rate, dissociation constant, substrate concentration, and catalytic rate constant. All values except K_D must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the dissociation rate constant (K_D)?
A: It's the ratio of reverse and forward rate constants, representing the equilibrium constant for enzyme-substrate dissociation.

Q2: How do I determine the catalytic rate constant (k_cat)?
A: k_cat is typically determined experimentally as the maximum number of substrate molecules converted to product per enzyme molecule per second.

Q3: What units should I use for substrate concentration?
A: The calculator uses mol/m³, but you can convert from molarity (M) by multiplying by 1000 (1 M = 1000 mol/m³).

Q4: Can K_D be zero?
A: Yes, if the enzyme-substrate complex doesn't dissociate, though this is rare in biological systems.

Q5: How does enzyme concentration affect reaction rate?
A: At constant substrate, reaction rate typically increases linearly with enzyme concentration until saturation occurs.