Initial Reaction Rate Formula:
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Definition: The Initial Reaction Rate (V0) is the speed at which a chemical reaction proceeds at the start of the reaction when substrate concentration is highest.
Purpose: This calculator helps biochemists and enzymologists determine the initial velocity of enzyme-catalyzed reactions using Michaelis-Menten kinetics.
The calculator uses the formula:
Where:
Explanation: The formula describes how the reaction rate depends on enzyme and substrate concentrations, and the enzyme's catalytic efficiency and substrate affinity.
Details: Measuring initial rates is crucial for understanding enzyme kinetics, determining kinetic parameters, and comparing enzyme efficiency under different conditions.
Tips: Enter the catalytic rate constant, initial enzyme concentration, substrate concentration, and dissociation constant. All values must be ≥ 0 (except kcat and [E0 which must be > 0).
Q1: What is kcat?
A: The catalytic rate constant (turnover number) represents the maximum number of substrate molecules converted to product per enzyme molecule per second.
Q2: What does KD represent?
A: The dissociation constant is a measure of enzyme-substrate affinity - lower values indicate tighter binding.
Q3: When is this formula applicable?
A: This applies to simple enzyme kinetics following Michaelis-Menten assumptions (steady-state, single substrate, etc.).
Q4: How do I determine kcat and KD experimentally?
A: These are typically determined by measuring initial rates at varying substrate concentrations and fitting the data.
Q5: What units should I use?
A: Consistent units are required - we use mol/m3 for concentrations (1 mol/m3 = 1 mM).