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Protein D2 porin of the Pseudomonas aeruginosa outer membrane bears the protease activity
Author(s) -
Yoshihara Eisaku,
Gotoh Naomasa,
Nishino Takeshi,
Nakae Taiji
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00945-3
Subject(s) - porin , protease , diisopropyl fluorophosphate , serine protease , bacterial outer membrane , chemistry , biochemistry , masp1 , proteases , enzyme , microbiology and biotechnology , biology , escherichia coli , gene
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 [ 3 H]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.