Concept explainers
To review:
The Km value for the inhibited and uninhibited reactions using a Michaelis–Menten plotis to be determined. The data for the enzyme-catalyzed hydrolysis reaction in the presence and absence of inhibitor is given as follows:
Substrate (moles) | V0 (micromoles per minute) | V0I (micromoles per minute) |
|
20.8 | 4.2 |
|
29 | 5.8 |
|
45 | 9 |
|
67.6 | 13.6 |
|
87 | 16.2 |
Introduction:
The Km value is defined as the substrate concentration at which half of the maximum velocity (1/2 Vmax) is achieved in the reaction. The inhibitors can be competitive (increase the Km value), uncompetitive (decrease the Km value), or non-competitive (do not alter the Km value), depending upon the mechanism used to inhibit the activity of the enzyme. The inhibitors act by decreasing the rate of a catalyzed reaction by interacting with free enzyme, enzyme–substrate complex, or both.
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Biochemistry: The Molecular Basis of Life
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