title: Increased nucleophile reactivity of amino acid beta-naphthylamides in alpha-chymotrypsin-catalyzed peptide synthesis.
abstract: Alpha-chymotrypsin-catalyzed acyl transfer from Boc-L-MetONp, Ac-L-TyrOEt, Bz-L-TyrOMe, Mal-L-PheOMe to the C-protected amino acids (L-AlaNH2, L-LeuNH2, L-ArgOMe and beta-naphthylamides of L-Arg, L-Leu, L-Ala and L-Glu) has been studied. Modification of the carboxylic groups with beta-naphthylamide was shown to increase the reactivity of nucleophiles in these reactions by a factor of more than 100 in comparison with amides and esters of the same amino acids. This effect can be accounted for by the effective formation of the nucleophile-acylenzyme complex due to hydrophobic interactions of the beta-naphthylamide moiety with the corresponding subsite of alpha-chymotrypsin. The reaction kinetics follows the scheme involving hydrolysis of the nucleophile-acylenzyme intermediate. The contribution of this pathway depends on the structures of both the acyl-group donor and the added nucleophile. The competitive inhibition by amino acid beta-naphthylamides is also observed. The results obtained show that modification of the COOH-group of added nucleophiles by beta-naphthylamide strongly affects the reactivity of these compounds in the alpha-chymotrypsin-catalyzed peptide synthesis.
authors.affiliation: Belozersky Laboratory of Molecular Biology and Bioorganic Chemistry, Moscow University, U.S.S.R.
authors.lastname: Gololobov MYu
authors.forename: A
authors.initials: A
authors.lastname: Petrauskas
authors.forename: R
authors.initials: R
authors.lastname: Pauliukonis
authors.forename: V
authors.initials: V
authors.lastname: Koschke
authors.forename: I L
authors.initials: IL
authors.lastname: Borisov
authors.forename: V
authors.initials: V
authors.lastname: Svedas
mesh_terms: D000217:Acyltransferases; D000596:Amino Acids / Q000378:metabolism*; D002918:Chymotrypsin / Q000378:metabolism*; D007202:Indicators and Reagents; D007700:Kinetics; D008433:Mathematics; D008962:Models, Theoretical; D009281:Naphthalenes / Q000378:metabolism; D010455:Peptides / Q000138:chemical synthesis*; D013379:Substrate Specificity
chemical_list: D000596:Amino Acids; D007202:Indicators and Reagents; D009281:Naphthalenes; D010455:Peptides; D000217:Acyltransferases; D002918:Chymotrypsin