BOVINE CATHEPSIN-S AND CATHEPSIN-L - ISOLATION AND AMINO-ACID-SEQUENCES

The purification procedure of cathepsin S includes acid activation of spleen homogenate, incubation at 37-degrees-C, precipitation with (NH4)2SO4 in H2O/tert-butanol medium, gel chromatography, chromatofocusing, covalent chromatography and cation chromatography on FPLC system. Cathepsin S has a M(r) of about 24 000 Da with pI of 6.5 and 6.8. The mixture of both forms gave a single sequence. Cathepsin L was purified from bovine kidney by acid treatment and incubation at 37-degrees-C, precipitation by (NH4)2SO4, two ion exchange chromatographies on CM-Sephadex, gel chromatography and ion exchange chromatography on FPLC system. Cathepsin L exists in multiple forms with pI 5,3 - 5,7 and M(r) of about 29 000 Da. N-terminal amino acid sequence confirms that cathepsin L and cathepsin S are different enzymes.