On the mechanism of the catalytic effect of carbohydrases: a review

摘要

Results of our studies and data from the literature on the mechanism of action of carbohydrases (enzymes catalyzing hydrolysis of oligosaccharides and polysaccharides) have been summarized. The values of pK and heat of ionization, pH dependences of the activity, and results of photooxidation studies suggest that carboxylic and imidazole groups are involved in the cleavage of glycoside bonds in oligosaccharides and polysaccharides. The mechanism of action is rationalized on the basis of the concept of oriented coupled attack of the bonds by nucteophilic and electrophilic groups in the enzyme active centers. The idea of the identity of the catalytic mechanisms of carbohydrases studied is advanced. It is concluded that the specificity of the effects of these enzymes is underlain by distinct mechanisms of the formation of enzyme-substrate complexes.