title: [Mechanism of oxygen exchange in the amide group of substrates during their hydrolysis catalyzed by leucine aminopeptidase and pepsin].
abstract: Oxygen exchange in the amide group of leucine amide catalyzed by leucine aminopeptidase, and in leucyltyrosine amide catalyzed by porcine pepsin, was found to proceed mainly by the transfer of the leucyl residue onto the ammonia or tyrosine amide which are formed during the hydrolysis. Thus oxygen exchange in the non-hydrolyzed substrate can not be a proof of the tetrahedral intermediate formation in the course of the catalysis by proteolytic enzymes.
mesh_terms: D000577:Amides / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D007700:Kinetics; D007908:Lens, Crystalline / Q000201:enzymology; D007931:Leucyl Aminopeptidase / Q000494:pharmacology*; D010100:Oxygen / Q000378:metabolism*; D010434:Pepsin A / Q000494:pharmacology*; D013379:Substrate Specificity
chemical_list: D000577:Amides; D007931:Leucyl Aminopeptidase; D010434:Pepsin A; D010100:Oxygen
vernacular_title: Mekhanizm obmena kisloroda v amidnoĭ gruppe substratov v khode ikh gidroliza, kataliziruemogo leĭtsinaminopeptidazoĭ i pepsinom.