Enzyme Substrate Dissociation Constant Formula:
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Definition: This is a modified dissociation constant that describes the affinity between an enzyme and its substrate when an uncompetitive inhibitor is present.
Purpose: It helps biochemists understand enzyme kinetics and inhibition patterns, which is crucial for drug development and metabolic studies.
The calculator uses the formula:
Where:
Explanation: The formula calculates the apparent dissociation constant by considering the concentrations of the enzyme-substrate complex, inhibitor, and the ternary complex.
Details: Understanding this constant is essential for studying enzyme inhibition mechanisms, designing enzyme inhibitors for therapeutic use, and analyzing metabolic pathways.
Tips: Enter the concentrations of enzyme-substrate complex, inhibitor, and enzyme-substrate-inhibitor complex. All values must be > 0 and in consistent units (mol/m³).
Q1: What distinguishes uncompetitive inhibition from other types?
A: Uncompetitive inhibitors bind only to the enzyme-substrate complex, not to the free enzyme, and this binding decreases both Km and Vmax.
Q2: How does Ki' relate to the original Ki?
A: Ki' is the apparent dissociation constant in presence of inhibitor, which differs from the inhibitor's intrinsic dissociation constant (Ki).
Q3: What are typical units for these measurements?
A: Concentrations are typically in mol/m³ or M (molar), and the dissociation constant has the same units.
Q4: How can I measure these complex concentrations?
A: These are typically determined through kinetic experiments using spectrophotometry or other enzyme activity assays.
Q5: What factors can affect the accuracy of this calculation?
A: Temperature, pH, ionic strength, and the presence of other modifiers can all influence the measured values.