A psychrotrophic bacterium producing a cold-adapted lipase upon growth th at low temperatures was isolated from Alaskan soil and identified as a Pseudomonas strain, The lipase gene (lipP) was cloned from the strain and sequenced, The amino acid sequence deduced from the nucleotide sequence of the gene (924 bp) corresponded to a protein of 308 amino acid residues with a molecular weight of 33,714. LipP also has consensus motifs conserved in other cold-adapted lipases, i.e., Lipase 2 from Antarctic Moraxella TA144 (G. Feller, M. Thiry, J. L. Arpigny, and C. Gerday, DNA Cell Biol. 10:381-388, 1991) and the mammalian hormone-sensitive lipase (D. Langin, H. Laurell, L. S. Hoist, P. Belfrage, and C. Holm, Proc. Natl. Acad. Sci. USA 90:4897-4901, 1993): a pentapeptide, GDSAG, containing the putative active-site serine and an BG dipeptide, LipP was purified from an extract of recombinant Escherichia coli C600 cells harboring a plasmid coding for the lipP gene, The enzyme showed a 1,3-positional specificity toward triolein, p-Nitrophenyl esters of fatty acids with short to medium chains (C-4 and C-6) served as good substrates. The enzyme was stable between pH 6 and 9, and the optimal pH for the enzymatic hydrolysis of tributyrin was around 8, The activation energies for the hydrolysis of p-nitrophenyl butyrate and p-nitrophenyl laurate were determined to be 11.2 and 7.7 kcal/mol, respectively. in the temperature range 5 to 35 degrees C, The enzyme was unstable at temperatures higher than 45 degrees C. The K-m of the enzyme for p-nitrophenyl butyrate increased with increases in the assay temperature, The enzyme was strongly inhibited by Zn2+, Cu2+, Fe3+, and Hg2+ but was not affected by phenylmethylsulfonyl fluoride and bis-nitrophenyl phosphate, Various water-miscible organic solvents, such as methanol and dimethyl sulfoxide, at concentrations of 0 to 30% (vol/vol) activated the enzyme.