Formula Used:
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Definition: The Catalytic Rate Constant (kcat) is defined as the rate constant for conversion of the enzyme-substrate complex to enzyme and product.
Purpose: This calculator helps determine the catalytic efficiency of an enzyme based on Michaelis-Menten kinetics parameters.
The calculator uses the formula:
Where:
Explanation: The formula calculates the catalytic rate constant by accounting for both forward and reverse reaction rates in enzyme kinetics.
Details: kcat is crucial for understanding enzyme efficiency, determining turnover number, and comparing different enzymes' catalytic power.
Tips: Enter the Michaelis Constant (KM), forward rate constant (kf), and reverse rate constant (kr). All values must be ≥ 0.
Q1: What is the typical range for kcat?
A: kcat values typically range from 1 to 107 s-1, depending on the enzyme and reaction.
Q2: How does kcat relate to enzyme efficiency?
A: Higher kcat values indicate more efficient enzymes that convert substrate to product faster.
Q3: What if my reverse rate constant is zero?
A: If kr = 0, the calculation simplifies to kcat = KM × kf.
Q4: How do I measure these constants experimentally?
A: KM and kcat are typically determined through initial rate measurements at varying substrate concentrations.
Q5: What's the relationship between kcat and Vmax?
A: Vmax = kcat × [E]total, where [E]total is the total enzyme concentration.