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

Formula Used:

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

mol/m³·s
mol/m³
mol/m³
s⁻¹
mol/m³

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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:

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 KD must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the dissociation rate constant (KD)?
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 (kcat)?
A: kcat 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 KD 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.

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