Peptide synthesis in organic media with subtilisin 72 immobilized on poly(vinyl alcohol)-cryogel carrier

Serine proteinase subtilisin 72 was covalently attached to the beads of poly(vinyl alcohol)-cryogel, a macroporous hydrogel prepared by the freeze–thaw technique. The immobilized enzyme was examined as a catalyst in the synthesis of protected peptides Z-Ala-Ala-Xaa-Phe-pNA (Xaa=Leu, Glu, Lys) in acetonitrile/dimethylformamide mixtures. Immobilized subtilisin catalyzed with high yield the formation of peptide bonds between Phe-pNA and acyl donors including those with free carboxylic group and non-protected C-terminal basic and acidic amino acid residues.