SDS-subtilisin catalyzed synthesis of tetra-peptides containing multifunctional amino acid residues in ethanol

The role of acyl donor structure on the course of peptide bond formation ca talyzed by SDS-subtilisin in ethanol was investigated. In the reaction Z-Al a-Ala-Leu-OR+H-Phe-pNA --> Z-Ala-Ala-Leu-Phe-pNA, nearly quantitative produ ct yields were observed after 2 h, regardless of whether an activated (R = CH3, p-C6H5Cl) or non-activated (R = H) acyl donor was used. It was found t hat the enzyme can accept as acyl donors N-protected tri-peptides containin g basic or acidic amino acid residues in the P-1-position. Tetra-peptides o f general formula Z-Ala-Ala-P-1-P-1'-pNA, where P-1 = Glu, Asp, Lys, Arg or His and P-1' = Phe, Arg or Glu have been obtained in good yield. (C) 2001 Elsevier Science B.V. All rights reserved.