title: Characterization of a new cold-adapted lipase from Pseudomonas sp. TK-3.
abstract: A psychrotrophic Pseudomonas sp. TK-3 was isolated from dirty and cool stream water in Toyama, Japan from which we cloned and characterized the bacterial lipase LipTK-3. The sequenced DNA fragment contains an open reading frame of 1,428 bp that encoded a protein of 476 amino acids with an estimated molecular mass of 50,132 Da. The lipase showed high sequence similarity to those of subfamily Ι.3 lipase and had a conserved GXSXG motif around the catalytic Ser residue. Its optimal temperature was 20-25 °C, lower than in most other subfamily Ι.3 lipases. The lipase exhibited about 30 % of maximal activity at 5 °C. The optimal pH value was 8.0. The activity was strongly inhibited by EDTA and was highly dependent on Ca(2+). Tricaprylin and p-nitrophenyl caprylate were the most favorable substrates among the triglycerides and p-nitrophenyl esters, respectively. LipTK-3 also showed high activity towards natural substrates including edible vegetable oils and animal fats. Furthermore, LipTK-3 was very active and stable in the presence of several detergents, metal ions, and organic solvents. This cold-adapted lipase may prove useful for future applications.
authors.affiliation: Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan. tanakada@sci.u-toyama.ac.jp
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tanaka
authors.forename: Satoru
authors.initials: S
authors.lastname: Yoneda
authors.forename: Yoko
authors.initials: Y
authors.lastname: Yamashiro
authors.forename: Akihiro
authors.initials: A
authors.lastname: Sakatoku
authors.forename: Takuro
authors.initials: T
authors.lastname: Kayashima
authors.forename: Kasumi
authors.initials: K
authors.lastname: Yamakawa
authors.forename: Shogo
authors.initials: S
authors.lastname: Nakamura
mesh_terms: D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D003080:Cold Temperature; D005618:Fresh Water / Q000382:microbiology; D008049:Lipase / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D011549:Pseudomonas / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*
chemical_list: D008049:Lipase