title: Protein D2 porin of the Pseudomonas aeruginosa outer membrane bears the protease activity.
abstract: We report here our discovery that protein D2 of the outer membrane of Pseudomonas aeruginosa is a novel porin bearing protease activity. Homogeneously purified protein D2 hydrolyzed several synthetic peptides according to the Michaelis-Menten kinetics. A specific serine protease inhibitor, diisopropyl fluorophosphate (DFP), inactivated the protease activity and [3H]DFP covalently labeled protein D2. We tested the effect of two monoclonal antibodies raised against protein D2 on the protease activity. One antibody lowered the protease activity to about 20%, while the other enhanced it to about 300% of that without antibody. In addition, the fractions derived from the outer membrane of the protein D2-deficient mutants showed negligible protease activity, whereas similarly fractionated outer membrane proteins of the protein D2-positive parent strain showed strong protease activity.
authors.affiliation: Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Japan.
authors.forename: E
authors.initials: E
authors.lastname: Yoshihara
authors.forename: N
authors.initials: N
authors.lastname: Gotoh
authors.forename: T
authors.initials: T
authors.lastname: Nishino
authors.forename: T
authors.initials: T
authors.lastname: Nakae
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D015153:Blotting, Western; D010450:Endopeptidases / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D007531:Isoflurophate / Q000494:pharmacology; D007700:Kinetics; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism; D018272:Porins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000737:chemistry* / Q000378:metabolism; D016415:Sequence Alignment; D012697:Serine Endopeptidases / Q000737:chemistry
chemical_list: D000911:Antibodies, Monoclonal; D010455:Peptides; D018272:Porins; D007531:Isoflurophate; C077157:OprD protein, Pseudomonas aeruginosa; D010450:Endopeptidases; D012697:Serine Endopeptidases