Kinetic Analysis of Conformational Change of Enzyme-ligand Complexes

Abstract

Conformational change occurring in the enzyme and/or enzyme-ligand complexes has been suggested, and evidences for it have been obtained by X-ray crystallography for some enzymes.
In the kinetic studies of enzyme-ligand interactions by the temperature-jump and stopped-flow methods, unimolecular isomerization processes of enzymes and/or enzyme-ligand complexes are frequently observed, which are attributable to a conformational change.
Unimolecular isomerization processes may be classified as follows, A) Conformational change of the enzyme only E_??_E* B) Conformational change of the enzyme-ligand complexes E·S_??_E·S* E·S_??_E*·S E·S_??_E*·S* where the mark * shows the "deformated state" of the enzyme or the ligand (E= enzyme, and S=ligand).
Examples for each case are reviewed for several enzymes including serine proteinases, lysozyme, RNAse, and aminoacylt-RNA synthetase.