title: Further characterization of buffalo spleen cathepsin B.
abstract: Cathepsin B (EC 3.4.22.1) from buffalo spleen was isolated to homogeneity and its molecular weight was determined to be 25 KDa. The enzyme was found to be a glycoprotein having a total carbohydrate content of 7%. The NH2- and COOH-terminal amino acid residues were identified as Leu and Thr, respectively. The specific extinction coefficient, E1%1cm, of the enzyme was determined to be 13.2. The value of intrinsic viscosity and equivalent hydrodynamic radius of the enzyme were calculated to be 3.47 ml/gm and 2.34 nm, respectively. Polyclonal antibodies raised in rabbits were found to cross-react distinctly with the purified buffalo enzyme. Using BANA as substrate, the Km and Vmax values were determined to be 0.93 mM and 5.57 Units/mg, respectively. The buffalo enzyme was also found to be highly active against protein substrates, and the Km values for casein and BSA were measured to be 1.12 and 1.74 microM, respectively.
authors.affiliation: Department of Biochemistry, School of Life Sciences, North-Eastern Hill University, Shillong, India.
authors.forename: S
authors.initials: S
authors.lastname: Ahmad
authors.forename: M Y
authors.initials: MY
authors.lastname: Khan
mesh_terms: D000818:Animals; D002020:Buffaloes; D002401:Cathepsin B / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D002845:Chromatography; D003429:Cross Reactions; D006023:Glycoproteins / Q000032:analysis; D007525:Isoelectric Focusing; D007700:Kinetics; D008970:Molecular Weight; D011817:Rabbits; D013056:Spectrophotometry, Ultraviolet; D013154:Spleen / Q000201:enzymology; D014783:Viscosity
chemical_list: D006023:Glycoproteins; D002401:Cathepsin B