title: [The heterogeneous character of protein modification during substitution of their amino groups. Acylation of alpha-chymotrypsin].
abstract: Thin-layer isoelectric focusing of chymotrypsin modified by stepwise acylation with acryloyl chloride or maleic anhydride revealed a high heterogeneity of modification products, with a maximal number of components near 50% of substituted amino groups. Disc electrophoresis failed to establish the products diversity and could not therefore be used for heterogeneity control. The activity of the modified enzyme towards proteins and low molecular weight substrates depended on the modification reagent and correlated with the electrostatic enzyme--substrate interaction. The low hydrolytic activity towards N-acetyl-L-tyrosine p-nitroanilide was due to the increase in the Michaelis constant; the value of the catalytic constant remained unchanged.
mesh_terms: D000179:Acrylates / Q000494:pharmacology; D000215:Acylation; D002918:Chymotrypsin / Q000378:metabolism*; D007700:Kinetics; D008299:Maleic Anhydrides / Q000494:pharmacology
chemical_list: D000179:Acrylates; D008299:Maleic Anhydrides; C026200:acryloyl chloride; D002918:Chymotrypsin
vernacular_title: Geterogennyĭ kharakter modifikatsii belkov pri zameshchenii ikh aminogrupp. Atsilirovanie al'fa-khimotripsina.