Enzymatic synthesis of chromogenic substrates for Glu,Asp-specific proteinases

Glu, Asp-specific endopeptidases represent a new subfamily of chymotrypsin- like proteolytic enzymes. These enzymes prefer Glu or Asp residues in the p i position of the substrates. p-Nitroanilides of N-acylated di-, tri- and t etrapeptides with C-terminal glutamic or aspartic acid residues have been o btained. Acyl peptide p-nitroanilides were synthesized via acylation of glu tamic or aspartic acid p-nitroanilides using methyl esters of the respectiv e N-acylated peptides, generally with good yields. The reactions were perfo rmed in organic solvents using subtilisin 72 sorbed on silica as a catalyst . The kinetic parameters for the hydrolysis of these p-nitroanilides with p roteinases from Bacillus intermedius and Bacillus licheniformis were determ ined.