@article{mbs:/content/journal/micro/10.1099/00221287-48-3-317, author = "Mencher, J. R. and Alford, J. A.", title = "Purification and Characterization of the Lipase of Pseudomonas fragi", journal= "Microbiology", year = "1967", volume = "48", number = "3", pages = "317-328", doi = "https://doi.org/10.1099/00221287-48-3-317", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-48-3-317", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", abstract = "SUMMARY: The lipase of Pseudomonas fragi (nrrl b-25) was purified 75-to 100-fold with an overall recovery of ca. 20%. The enzyme was found to exist in heavy and light forms exhibiting the same position specificity for triglycerides, Michaelis constants (Km), and apparent pH and temperature optima. The light form of the enzyme appeared to be present in the heavy one, probably in a complexed state. The purified lipase was found to hydrolyze only glycerol esters of fatty acids; it required a water-fat interface and exhibited a 1,3-position specificity for triglycerides. The optimum pH for the purified enzyme with purified tributyrin as substrate was calculated to be 8.6 to 8.7 from initial velocity measurements with a pH-stat at 25°. The Km for the purified lipase with tributyrin was found to be 0.9 x 10−3 m at 25°and pH 7.2. Exposure of the purified enzyme to 40°for 10 min. caused a complete loss of activity. A 50% loss of activity-occurred after 10 min. exposure to about 35°. When exposed to pH values ranging from 5.3 to 9.5 for 1 hr at 2°and then assayed at pH 7.0 and 35°, the purified enzyme was found to be stable in the pH range 6.6-7.8.", }