title: Cathepsins B and H from porcine spleen. Purification, polypeptide chain arrangements, and carbohydrate content.
abstract: Procedures for the purification of cathepsins B and H from porcine spleens have been described. The purified porcine cathepsin B (Mr = 27,000) is predominantly a two-chain enzyme with a heavy chain (Mr = 22,000) and a light chain (Mr = 5,000). It also contains two minor forms of cathepsin B with different chain structures. Porcine cathepsin H is a single-chain enzyme with a molecular weight of 25,000. The carbohydrate analyses showed that these enzymes were glycoproteins. A glycopeptide containing 3 amino acids, 2 glucosamines, and 6 mannoses was isolated from cathepsin H. Proton NMR studies revealed that it contained a mixture of 4 high mannose-type of oligosaccharides characteristic of those found on lysosomal enzymes. The carbohydrate of cathepsin B consisted of a single residue of glucosamine and trace mannose. This sugar content is in agreement with the finding that about 80% of the porcine spleen cathepsin B contained a single N-acetylglucosamine while 20% of the enzyme contained a 5-sugar oligosaccharide (Takahashi, T., Schmidt, P. G. and Tang, J. (1984) J. Biol. Chem. 259, 6059-6062). Thus, the studies on carbohydrate contents also indicated the good purity of the enzymes.
mesh_terms: D000117:Acetylglucosamine / Q000032:analysis; D000595:Amino Acid Sequence; D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D002401:Cathepsin B; D056655:Cathepsin H; D002403:Cathepsins / Q000302:isolation & purification*; D003546:Cysteine Endopeptidases; D005944:Glucosamine / Q000032:analysis; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D008358:Mannose / Q000032:analysis; D008970:Molecular Weight; D051381:Rats; D013154:Spleen / Q000201:enzymology*; D013329:Structure-Activity Relationship; D013552:Swine
chemical_list: D002241:Carbohydrates; D046911:Macromolecular Substances; D002403:Cathepsins; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; D056655:Cathepsin H; C534128:Ctsh protein, rat; D005944:Glucosamine; D008358:Mannose; D000117:Acetylglucosamine