title: Purification and characterization of a novel extracellular tripeptidyl peptidase from Rhizopus oligosporus.
abstract: A novel extracellular tripeptidyl peptidase (TPP) was homogenously purified from the culture supernatant of  Rhizopus oligosporus  by sequential fast protein liquid chromatography. The purified enzyme was a 136.5 kDa dimer composed of identical subunits. The effects of inhibitors and metal ions indicated that TPP is a metallo- and serine protease. TPP was activated by divalent cations, such as Co(2+) and Mn(2+), and completely inhibited by Cu(2+). Enzyme activity was optimal at pH 7.0 and 45 °C with a specific activity of 281.9 units/mg for the substrate Ala-Ala-Phe-pNA. The purified enzyme catalyzed cleavage of various synthetic tripeptides but not when proline occupied the P1 position. Purified TPP cleaved the pentapeptide Ala-Ala-Phe-Tyr-Tyr and tripeptide Ala-Ala-Phe, confirming the TPP activity of the enzyme.
authors: Department of Biotechnology, Hungkuang University, 34 Chung-Chie Road, Taichung 43302, Taiwan.
authors: Jia-Shin
authors: JS
authors: Lin
authors: Shuo-Kang
authors: SK
authors: Lee
authors: Yeh
authors: Y
authors: Chen
authors: Wei-De
authors: WD
authors: Lin
authors: Chao-Hung
authors: CH
authors: Kao
mesh_terms: D000595:Amino Acid Sequence; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D012233:Rhizopus / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases