[pH-dependence of the mechanism of pepsin action].
N-Acetyl-L-phenylalanine inhibition of the peptic hydrolysis of N-acetyl-L-phenylalanine-L-tyrosine over the pH range 2-4.5 was studied. The mixed character of inhibition which was partially competitive and partially non-competitive allowed us to infer that the separate steps of the enzymatic hydrolysis were pH dependent. The orderliness of the dissociation of the triple enzyme-product-product complex was also pH dependent. The group with pKa approximately 3 influenced the mechanisms of pepsin hydrolysis as strongly as in the case of pepsin catalyzed oxygen isotopic exchange in the acyl amino acid carboxyl group.
D001665:Binding Sites; D001667:Binding, Competitive; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010434:Pepsin A / Q000378:metabolism*; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000494:pharmacology; D011485:Protein Binding
D010649:Phenylalanine; D010434:Pepsin A
Zavisimost' ot velichiny pN mekhanizma deĭstviia pepsina