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Dissociation Rate Constant given Concentration of Enzyme and Substrate Calculator

Dissociation Rate Constant Formula:

\[ K_D = \frac{(V_{max} \times S)}{V_0} - S \]

mol/m³·s
mol/m³
mol/m³·s
mol/m³

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1. What is Dissociation Rate Constant?

Definition: The Dissociation Rate Constant (KD) is the ratio of the reverse and forward rate constants in enzyme-substrate interactions.

Purpose: It helps biochemists understand the binding affinity between enzymes and substrates, which is crucial for studying enzyme kinetics.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ K_D = \frac{(V_{max} \times S)}{V_0} - S \]

Where:

Explanation: The formula calculates the equilibrium dissociation constant which represents the substrate concentration at which the reaction rate is half of Vmax.

3. Importance of Dissociation Rate Constant

Details: KD is a key parameter in enzyme kinetics that indicates how tightly a substrate binds to an enzyme. Lower values indicate stronger binding.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What does a high KD value indicate?
A: A high KD indicates weak binding between the enzyme and substrate, meaning the enzyme has low affinity for that substrate.

Q2: How is KD related to enzyme efficiency?
A: Generally, enzymes with lower KD values for their substrates are more efficient as they can bind substrates more tightly.

Q3: What are typical units for KD?
A: KD is typically expressed in molar concentration units (mol/m³ or M).

Q4: How does temperature affect KD?
A: Temperature changes can affect KD as both binding and dissociation rates are temperature-dependent.

Q5: What's the relationship between KD and Km?
A: For simple Michaelis-Menten kinetics, Km approximates KD when the catalytic step is much slower than dissociation.

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