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J Bacteriol. 1975 March; 121(3): 933-941

Purification and properties of a serine protease from Pseudomonas matophilia.

ABSTRACT

The extracellular protease of Pseudomonas maltophilia was partially purified by ammonium sulfate precipitation and chromatography on Sephadex G-75 and Bio-rex 70. Gel electrophoresis revealed minor impurities. The enzyme exhibited the following properties: (i) molecular weight, 35,000; (ii) A see article; 10.8; (iii) isoelectric point, 9.3; (iv) pH optimum, 10.0; (v)s20, w equal 3.47. The enzyme was rapidly inactivated by ethylenediaminetetracetate, but activity could be partially restored with divalent cations. Of those tested, Ca2+, Sr2+, Ba2+, Co2+, Cu2+, Mg2+, and Zn2+ were all effective. Both phenylmethylsulfonylfluoride and diisopropylfluorophosphate were powerful inhibitors of protease activity, but L-1-tosylamide-2-phenylethylchloromethyl ketone, iodoacetic acid, and iodoacetamide were without effect. The enzyme hydrolyzed the esters N-acetyl-L-tyrosine ethyl ester and alpha-N-benzoyl-L-arginine ethyl ester (BAEE) with Km values of 10.4 and 3.4 mM, respectively. The hydrolysis of BAEE was also inhibited by phenylarsonic acids. The kinetics of inhibition by m-nitrophenylarsonate were of the mixed type, and the K1 was 1.8 mM. The data followed a theoretical curve for a 1:1 enzyme-inhibitor complex with a dissociation constant of 1.8 mM. Inhibition by m-nitrophenylarsonate was pH dependent and followed a theoretical curve for the titration of a protonated group with a pKa of 7.0.

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• Windhorst, S., Frank, E., Georgieva, D. N., Genov, N., Buck, F., Borowski, P., Weber, W. (2002). The Major Extracellular Protease of the Nosocomial Pathogen Stenotrophomonas maltophilia. CHARACTERIZATION OF THE PROTEIN AND MOLECULAR CLONING OF THE GENE. J. Biol. Chem. 277: 11042-11049 [Abstract] [Full Text]  
• Denton, M., Kerr, K. G. (1998). Microbiological and Clinical Aspects of Infection Associated with Stenotrophomonas maltophilia. Clin. Microbiol. Rev. 11: 57-80 [Abstract] [Full Text]