1 Steady State Kinetics

Abstract

This chapter discusses the kinetics of the steady state—that is, to conditions where the reactant concentrations and their Michaelis constants greatly exceed that of the catalyst or where there is a dynamic steady state with substrates being continually supplied and products continually removed. Kinetic mechanisms fall into two major groups. Those in which all reactants must combine with the enzyme before reaction can take place and any products be released are called “sequential.” Mechanisms in which one or more products are released before all substrates have added are called “ping pong;” in such mechanisms the enzyme oscillates between two or more stable enzyme forms, while in sequential mechanisms there is only one stable enzyme form. Sequential mechanisms are called ordered, if reactants combine with the enzyme and dissociate in obligatory order or random if alternate pathways exist and the order of combination or release is not obligatory.