Isolation of milk-clotting enzyme from transgenic sheep milk and its comparison with calf chymosin

Technology for preparation of chymosin from milk of transgenic sheep has be en elaborated. purification of the preparation by ion-exchange chromatograp hy on aminosilochrom and biospecific chromatography on bacitracin-Sepharose yielded homogeneous active enzyme. Hydrolysis of protein substrates (hemog lobin, BSA, and sodium caseinate) by the transgenic sheep chymosin and stab ility of the enzyme at various values of pH were studied. Judging by the am ino acid composition, the N-terminal sequence involving six amino acid resi dues, molecular mass, stability at various pH values, and the catalytic act ivity against the protein substrates, the transgenic sheep chymosin is iden tical to calf chymosin.