Substrate Concentration given Dissociation Rate Constant Calculator

Substrate Concentration Formula:

\[ S = \frac{K_D \times [ES]}{[E_0] - [ES]} \]

Dissociation Rate Constant (K_D):

mol/m³

Enzyme Substrate Complex Concentration ([ES]):

mol/m³

Initial Enzyme Concentration ([E₀]):

mol/m³

Substrate Concentration (S): mol/m³

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1. What is Substrate Concentration given Dissociation Rate Constant?

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

Purpose: It helps biochemists and enzymologists understand enzyme kinetics and the relationship between substrate concentration and enzyme-substrate complex formation.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ S = \frac{K_D \times [ES]}{[E_0] - [ES]} \]

Where:

\( S \) — Substrate concentration (mol/m³)
\( K_D \) — Dissociation rate constant (mol/m³)
\( [ES] \) — Enzyme-substrate complex concentration (mol/m³)
\( [E_0] \) — Initial enzyme concentration (mol/m³)

Explanation: The formula calculates the substrate concentration required to achieve a specific enzyme-substrate complex concentration given the enzyme's dissociation constant.

3. Importance of Substrate Concentration Calculation

Details: Accurate substrate concentration determination is crucial for enzyme kinetics studies, drug discovery, and understanding metabolic pathways.

4. Using the Calculator

Tips: Enter the dissociation rate constant (K_D), enzyme-substrate complex concentration ([ES]), and initial enzyme concentration ([E₀]). All values must be > 0 and [E₀] must be greater than [ES].

5. Frequently Asked Questions (FAQ)

Q1: What is the dissociation rate constant (K_D)?
A: It's the ratio of the reverse and forward rate constants in enzyme-substrate binding, representing the substrate concentration at which half of the enzyme is bound.

Q2: How is [ES] measured experimentally?
A: [ES] can be measured using spectroscopic methods, calorimetry, or other techniques that detect the enzyme-substrate complex.

Q3: What if [E₀] equals [ES]?
A: The denominator becomes zero, which is mathematically undefined. Physically, this means all enzyme is bound to substrate.

Q4: What units should I use?
A: The calculator uses mol/m³, but you can use any consistent units as long as all inputs use the same units.

Q5: How does temperature affect the calculation?
A: Temperature affects K_D values, so ensure your K_D was measured at the same temperature as your experiment.