FREE TRYPSIN-CATALYZED PEPTIDE-SYNTHESIS IN ACETONITRILE WITH LOW WATER-CONTENT

The reactions of Bz-Arg-OEt, Boc-Lys-OMe and Boc-Tyr-Lys-OMe with various amino acid amides and peptides, catalyzed by free trypsin in acetonitrile in the presence of triethylamine and 5 vol. % of water, were studied. The synthesis of Bz-Arg-Leu-NH2 was strongly dependent on the water content (from 2 to 10%) in the reaction medium. Excess of base (triethylamine) had no negative effect on the reaction. The reaction proceeded analogously also in some aliphatic alcohols but not in dimethylformamide.