RESUMEN
Commercial preparations of trypsin, varying in activity, were immobilized in a cryogel of polyvinyl alcohol, activated by dialdehydes (terephthalic, succinic, or glutaric) or divinyl sulfone. All preparations of the immobilized enzyme exhibited hydrolytic activity and retained stability for 8 months. In an organic solvent environment, specimens of immobilized trypsin catalyzed the synthesis of N-carbobenzoxy-L-phenylalanyl-L-arginyl-L-leucine p-nitroanilide from N-carbobenzoxy-L-phenylalanyl-L-argininine methyl ester (or N-carbobenzoxy-L-phenylalanyl-L-arginine) and L-leucine p-nitroanilide, as well as the formation of N-carbobenzoxy-L-alanyl-L-alanyl-L-arginyl-L-phenylalanine p-nitroanilide from N-carbobenzoxy-L-alanyl-L-alanyl-L-arginine and L-phenylalanine p-nitroanilide. The presence of small amounts of water in organic solvents was prerequisite to the biocatalysts manifesting synthase activity in reactions of peptide bond formation.