title: Production and properties of lipase of Aeromonas sobria.
abstract: Aeromonas have been isolated from a wide variety of aquatic environments. However the number of Aeromonas in sea water is extremely small compared to that in fresh water. In in vitro culture, Aeromonas can grow in mediums containing NaCl at a concentration of 3.0%, this concentration corresponding to that of sea water. It is unclear why the number of Aeromonas is low in sea water. Exoproteins of bacteria are thought to be important for bacterial growth and survival in the environment. Previously, the present authors have shown that mediums containing 3.0% NaCl suppress production of two proteases, serine protease and metalloprotease. In this experiment, other exoproteins whose production is influenced by the amount of NaCl in the medium were analyzed. A protein whose production is repressed in medium containing 3.0% NaCl was found and purified. Biological assay of the purified protein showed that it degrades tributyrin and hydrolyzes para-nitrophenyl-fatty acylesters. These results show that the protein is a lipase. Subsequently, the nucleotide sequence of the gene encoding the lipase was determined and the amount of mRNA of the lipase gene in the cells measured. It was found that transcription of the gene is not inhibited by NaCl in the medium. This result indicates that the lipase might be synthesized, but the folding process to become an active structure does not progress smoothly in a medium containing 3.0% NaCl.
authors.affiliation: Laboratory of Protein Function, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Kitaku, Okayama, Japan. takahashi@pharm.okayamau.ac.jp
authors.forename: Eizo
authors.initials: E
authors.lastname: Takahashi
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Ito
authors.forename: Hidetomo
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Yamanaka
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Takeda
authors.forename: Gopinath
authors.initials: G
authors.lastname: Balakrish Nair
authors.forename: Sakae
authors.initials: S
authors.lastname: Arimoto
authors.forename: Tomoe
authors.initials: T
authors.lastname: Negishi
authors.forename: Keinosuke
authors.initials: K
authors.lastname: Okamoto
mesh_terms: D000333:Aeromonas / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D003470:Culture Media / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D008049:Lipase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D021381:Protein Transport; D012623:Seawater / Q000382:microbiology; D016415:Sequence Alignment; D012965:Sodium Chloride / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D012965:Sodium Chloride; D008049:Lipase