title: Purification and characterization of a 43-kilodalton extracellular serine proteinase from Cryptococcus neoformans.
abstract: An extracellular proteinase was purified from culture filtrates of Cryptococcus neoformans NHPY24 by DEAE ion-exchange chromatography and gelatin affinity column chromatography with azoalbumin as the substrate. The molecular mass of the purified enzyme was 43 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, its pH optimum was 7.0 to 8.0, and maximal activity was obtained at pH 7.5 and 37 degrees C. By isoelectric focusing, the purified enzyme had a pI of 4.77. Enzyme activity was inhibited by serine proteinase inhibitors such as phenylmethylsulfonyl fluoride and diisopropylfluorophosphate. The purified enzyme was thus a serine proteinase. It hydrolyzed natural substrates including hemoglobin, beta-casein, and gamma globulin.
authors.affiliation: Laboratory of Antimicrobial Resistant Pathogens, Department of Bacteriology, National Institute of Health, Chung-Ang University, Seoul, Korea.
authors.forename: Jae il
authors.initials: Ji
authors.lastname: Yoo Ji
authors.forename: Yeong Seon
authors.initials: YS
authors.lastname: Lee
authors.forename: Chul-Yong
authors.initials: CY
authors.lastname: Song
authors.forename: Bong Su
authors.initials: BS
authors.lastname: Kim
mesh_terms: D003455:Cryptococcus neoformans / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D012697:Serine Endopeptidases / Q000302:isolation & purification* / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D013379:Substrate Specificity; D013816:Thermodynamics
chemical_list: D015842:Serine Proteinase Inhibitors; D012697:Serine Endopeptidases