Physicochemical and biological properties of an extracellular serine protease of Aeromonas sobria

Ritsuko Yokoyama, Yoshio Fujii, Yoko Noguchi, Tomohiko Nomura, Masahiko Akita, Kojun Setsu, Shigeo Yamamoto, Keinosuke Okamoto

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


Previously, we cloned a protease gene of Aeromonas sobria, determined its nucleotide sequence and established a method of purifying its product. In this study, we examined the properties of the purified protease. The protease was temperature-labile and had an optimal pH of 7.5. Metallo-protease inhibitors and a cysteine protease inhibitor did not block the proteolytic activity of the enzyme. The treatment with reagents to modify sulfhydryl group did not reduce the activity. But, serine protease inhibitors did, showing that it was a serine protease. Subsequently, we examined the ability of the protease to enhance vascular permeability in dorsal skin. The protease showed activity and the reaction was inhibited by a simultaneously injected antihistaminic agent. Histopathological examination showed that mast cells appeared around the site where the protease was injected. These findings show that the vascular permeability-enhancing effect of the protease is due to histamine released at the site. Furthermore, we found that a soybean trypsin inhibitor (Kunitz) did not block the proteolytic action of the protease in vitro, but inhibited its vascular permeability-enhancing activity in skin. This suggests that a trypsin-like protease from skin mediates the activity of the protease to enhance its vascular permeability.

Original languageEnglish
Pages (from-to)383-390
Number of pages8
Issue number6
Publication statusPublished - 2002
Externally publishedYes


  • Aeromonas
  • Inhibitor
  • Permeability
  • Protease

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Virology


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