Peptide synthesis catalyzed by papain at alkaline pH values

Abstract

The synthesis of peptides in the presence of papain at pH 8–9.5 is described. Starting substances are acylamino acid alkyl esters (the carboxyl component) and amides or tert.‐butylesters of amino acids, as well as peptide (the amino component). Under such conditions secondary hydrolysis is not essential, making the synthesis of peptides soluble in aqueous medium. The yield of peptides is 50–94%. The effect of different factors (temperature, solvents, reagent concentrations) on the result of the reaction has been studied. It has been found that an excess of the carboxyl component is expedient to increase the yield of peptides.

Thio‐α‐amino acids (S‐acids) as a carboxyl component in peptide synthesis catalysed by papain

“…The oxygen analog, Z-AlaOH, does not interact with papain in these conditions. An analogous result was obtained earlier for benzoylalanine methyl ester (7) and for water soluble glycolyl glycine ester of benzoylalanine (10). It is interesting that the maximal rate of Z-AlaSH hydrolysis catalysed by papain is observed at pH 4.5 ( Fig.…”

“…3) the precipitate was filtered off, washed with water, and dried at 100' to a constant weight, R, 0.42 (chloroform:methanol, 9: l), m.p. 246-247' (7). were added.…”

Enzymatic synthesis of dipeptide units of the d‐d‐configuration in aqueous media

“…The isolated enzyme preparation, containing muramoyl-pentapeptide carboxypeptidase (D-alanine carboxypeptidase, E.C.3.4.17.8), showed several To investigate whether amino acids or their derivatives were the best nucleophiles, syntheses were performed with H-D-Ala-OH, H-D-Ala-OMe, H-D-Ala-NH,, H-D-Ala-OBu', H-D-Ser-OH, H-D-Ser-OMe, H-DL-Thr-OH, and H-D-Thr-OMe (Table 1). Peptide products were formed in all cases, but the unmodified amino acids resulted in higher yields than when the corresponding derivatives were used, in contrast to studies using other proteolytic enzymes (22,27).…”

Chymotrypsin catalysed synthesis of fluorescent amino acid amide and peptide derivatives

“…After the discovery that a-chymotrypsin can be employed to accomplish both hydrolysis and synthesis of a peptide bond (I), the enzymecatalysed synthesis of peptides has undergone intensive development (2)(3)(4)(5)(6)(7) and is considered at present a viable alternative t o the purely chemical synthesis.…”