Dynamic aspects of enzyme specificity

Abstract

There are two aspects of enzyme specificity: recognition of the substrate by the formation of an enzyme-substrate compound and recognition of the transition state by catalysis of the reaction. Kinetic studies with inactive substrate analogues as potential competitive inhibitors, and structural studies of their compounds with enzymes, give information about the first of these specificity elements. Comparative kinetic studies with alternative substrates give information about both. There is a great deal of information from kinetic studies of dehydrogenases about the coenzyme specificities, substrate specificities and stereospecificities and mechanisms of these enzymes, particularly alcohol dehydrogenases. Recent X-ray diffraction studies of dehydrogenases have given insight into the molecular basis of some of their specificity elements. An attempt is made to correlate the available kinetic and structural data for alcohol and lactate dehydrogenases.