Substrate Concentration Formula:
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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.
The calculator uses the formula:
Where:
Explanation: The formula calculates the substrate concentration required to achieve a specific enzyme-substrate complex concentration given the enzyme's dissociation constant.
Details: Accurate substrate concentration determination is crucial for enzyme kinetics studies, drug discovery, and understanding metabolic pathways.
Tips: Enter the dissociation rate constant (KD), enzyme-substrate complex concentration ([ES]), and initial enzyme concentration ([E0]). All values must be > 0 and [E0] must be greater than [ES].
Q1: What is the dissociation rate constant (KD)?
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 KD values, so ensure your KD was measured at the same temperature as your experiment.