One-substrate-one-product enzymic reactions: The relationship between isotope-exchange kinetic, steady-state kinetic and equilibrium parameters

✍ Scribed by I.G. Darvey

• Publisher: Elsevier Science
• Year: 1975
• Tongue: English
• Weight: 464 KB
• Volume: 49
• Category: Article
• ISSN: 0022-5193
• DOI: 10.1016/s0022-5193(75)80028-2

✦ Synopsis

Expressions are derived for the parameters that can be obtained from (1) steady-state kinetics, (2) isotope-exchange kinetics at equilibrium, and (3) equilibrium binding experiments for the following two one-substrateone-product enzymic mechanisms:

It is shown that the exchange constants for both mechanisms are identical with the reciprocals of the equilibrium parameters that can be obtained from binding experiments. Therefore, expressions relating isotope exchange constants and steady-state kinetic parameters are analogous to those relating equilibrium parameters and steady-state kinetic parameters.

The paper also presents, for mechanisms I and II, relationships between the maximum rate of isotope-exchange at equilibrium and the steady-state kinetic parameters. These relationships provide a new criterion for distinguishing experimentally between these two mechanisms.