title: Purification and some properties of proteinase from Pseudomonas fluorescens No. 33.
abstract: The extracellular proteinase from Pseudomonas fluorescens No. 33 was purified to electrophoretic homogeneity by a procedure including precipitation with HCl and (NH4)2SO4, and column chromatography. The enzyme was purified 170-fold giving a yield of 7% of the original activity. The molecular mass of the purified enzyme was 48,000 by SDS-PAGE. The optimum pH and temperature for the hydrolysis of casein were 8.0-9.8 and 30-35 degrees C respectively. The enzyme was more thermostable in synthetic milk salts solution than in 0.1 M-sodium phosphate buffer, but was heat-labile at 50 degrees C in both buffer systems. The activity was inhibited by o-phenanthroline, Hg2+, Cu2+, Fe2+ and, to a lesser extent, Ni2+. Caseins were susceptible to the proteinase, but degradation patterns were dependent on the form of the casein.
authors.affiliation: Laboratory of Dairy Science, Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kumura
authors.forename: K
authors.initials: K
authors.lastname: Mikawa
authors.forename: Z
authors.initials: Z
authors.lastname: Saito
mesh_terms: D002364:Caseins / Q000378:metabolism; D003300:Copper / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007501:Iron / Q000494:pharmacology; D008628:Mercury / Q000494:pharmacology; D008970:Molecular Weight; D009532:Nickel / Q000494:pharmacology; D010618:Phenanthrolines / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D011551:Pseudomonas fluorescens / Q000201:enzymology*; D013696:Temperature
chemical_list: D002364:Caseins; D010618:Phenanthrolines; D011480:Protease Inhibitors; D003300:Copper; D009532:Nickel; D007501:Iron; D010450:Endopeptidases; D008628:Mercury; C025205:1,10-phenanthroline