SEQUENTIAL ATTACHMENT OF ARGININE RESIDUE S TO PEPTIDES CATALYZED BY SUBTILISIN .2. EFFECT OF THE NATURE OF ACYLATION AND NUCLEOPHILIC COMPONENTS AND SMALL WATER CONCENTRATIONS IN ORGANIC-SOLVENT

The reaction of Dnp(or Z)Ala(2)-Xaa-OCH3 (Xaa = Ile or Val) with argin ine amide or p-nitroanilide was studied in organic solvents, which was catalyzed by subtilisin sorbed on macroporous glass. It resulted in t he formation of peptides,containing one to four arginine residues: Dnp (or Z)-Ala(2)-Xaa-(Arg)(1-4)-NH2. The number of arginine residues atta ched to the peptide depended on the water content in organic solvents, nature of the amino acid residue Xaa in the P-1 position of the acyla ting component, and the type of the N-protective group. The reaction c an be used for synthesizing arginine-containing substrates of converta ses and cathepsins B, L, and O. A chromogenic substrate for duodenase Z-Ala(2)-Ile-Arg(2)-pNA was obtained.