Catalytic Rate Constant Formula:
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Definition: The Catalytic Rate Constant (kcat) is the rate constant for conversion of the enzyme-substrate complex to enzyme and product.
Purpose: It measures the turnover number of an enzyme, indicating how many substrate molecules one enzyme molecule can convert to product per second.
The calculator uses the formula:
Where:
Explanation: The formula relates the initial reaction rate to enzyme and substrate concentrations, accounting for enzyme-substrate dissociation.
Details: kcat is crucial for understanding enzyme efficiency, comparing different enzymes, and predicting reaction rates under various conditions.
Tips: Enter all required values in appropriate units. Ensure substrate and enzyme concentrations are positive values.
Q1: What does a high kcat value indicate?
A: A high kcat means the enzyme is very efficient, converting many substrate molecules per second.
Q2: How is kcat related to enzyme efficiency?
A: kcat is part of the catalytic efficiency measure (kcat/KM), where higher values indicate more efficient enzymes.
Q3: What are typical kcat values?
A: Most enzymes have kcat values between 1 and 10⁶ s⁻¹, with very efficient enzymes at the higher end.
Q4: Can kcat exceed 10⁶ s⁻¹?
A: Extremely rare, as this approaches the diffusion limit of molecular encounters in solution.
Q5: How does temperature affect kcat?
A: Like most rate constants, kcat typically increases with temperature up to the enzyme's denaturation point.