Protein D2 porin of the Pseudomonas aeruginosa outer membrane bears the protease activity

FEBS Lett. 1996 Sep 30;394(2):179-82. doi: 10.1016/0014-5793(96)00945-3.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antibodies, Monoclonal / immunology
  • Blotting, Western
  • Endopeptidases / chemistry
  • Endopeptidases / immunology
  • Endopeptidases / metabolism*
  • Isoflurophate / pharmacology
  • Kinetics
  • Molecular Sequence Data
  • Peptides / metabolism
  • Porins / chemistry
  • Porins / immunology
  • Porins / isolation & purification
  • Porins / metabolism*
  • Pseudomonas aeruginosa / chemistry*
  • Pseudomonas aeruginosa / metabolism
  • Sequence Alignment
  • Serine Endopeptidases / chemistry


  • Antibodies, Monoclonal
  • Peptides
  • Porins
  • Isoflurophate
  • OprD protein, Pseudomonas aeruginosa
  • Endopeptidases
  • Serine Endopeptidases