A Thermodynamic Cycle Analysis

A thermodynamic cycle showing how catalysis can be directly related to the differential binding of the substrate and the transition state. 

The reason for this is that enzymes have evolved to execute their reactions within a specific time period appropriate for the metabolism of life. The reactions of life have to occur at a rate commensurate with metabolism and other life processes, and thus the rate constants for the enzymatic reactions fall within a fairly narrow range. For most biochemical processes, reactions that occur on the millisecond to microsecond time scale are fast enough. 

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