Catalytic Rate Constant Formula:
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Definition: The catalytic rate constant (kcat) represents the number of substrate molecules converted to product per enzyme molecule per second when the enzyme is saturated with substrate.
Purpose: It measures the enzyme's turnover rate and is a key parameter in enzyme kinetics studies.
The calculator uses the formula:
Where:
Explanation: The formula calculates how efficiently an enzyme converts substrate to product under specified conditions.
Details: kcat is crucial for understanding enzyme efficiency, comparing different enzymes, and predicting reaction rates under various conditions.
Tips: Enter the initial reaction rate, Michaelis constant, substrate concentration, and initial enzyme concentration. All values must be positive (except KM which can be zero).
Q1: What does a higher kcat value indicate?
A: Higher kcat means the enzyme can convert more substrate molecules per second, indicating greater catalytic efficiency.
Q2: How is kcat related to Vmax?
A: Vmax = kcat × [E0], where [E0] is the total enzyme concentration.
Q3: What's a typical range for kcat values?
A: Most enzymes have kcat values between 1 and 10⁶ s⁻¹, with very efficient enzymes at the higher end.
Q4: How does kcat relate to enzyme efficiency?
A: The catalytic efficiency is often expressed as kcat/KM, combining both turnover rate and substrate affinity.
Q5: Can kcat be greater than 1?
A: Yes, values >1 mean each enzyme molecule processes multiple substrate molecules per second.