Enzymatic synthesis of peptides using N-protected racemic amino acids as carboxyl components

Condensation of the N-Z- or N-Boc-protected DL-amino acids (or esters) with GlyNHNHPh in the presence of papain at pH=5.0(or 8.2) or alpha-chymotrypsin at pH=10.0 formed the expected optically active protected oligopeptides. The reaction was carried out in an aqueous-organic mixed solvent system and non-aqueous solvent system. These results indicate that the amino acid ester as acyl donor was better than the corresponding acid, The GlyNHNHPh as nucleophilic reagent was better than the corresponding ester, Both thermal and storage stabilities of alpha-chymotrypsin are greatly enhanced in nonaqueous solvents compared with water system, The enzymatic peptide synthesis could also be carried out in dichloromethane with micro essential water (0.25%) and satisfactory results could be obtained.Chemistry, MultidisciplinarySCI(E)中文核心期刊要目总览(PKU)中国科学引文数据库(CSCD)0155-591