title: Purification and characterization of two distinct lipases from Geotrichum candidum.
abstract: Lipase, an enzyme that hydrolyzes triacylglycerol, has been purified and characterized. The purification procedure includes ethanol precipitation and chromatographies on Sephacryl-200 HR, high resolution anion-exchange (mono Q) and Polybuffer exchanger 94. With this procedure, two forms of lipases from Geotrichum candidum were obtained. Lipase I (main enzyme) and lipase II (minor enzyme) were purified 35-fold with a 62% recovery in activity and 94-fold with a 18% recovery in activity, respectively. Their molecular weights have been estimated by polyacrylamide gel electrophoresis under denaturing conditions and by molecular sieving under native conditions at 56,000. Lipase I and II had optimum pH values of 6.0 and 6.8 and isoelectric points of 4.56 and 4.46, respectively. The enzymes are stable at a pH range of 6.0 to 8.0. Monovalent ions had little effect on both enzyme activities, while divalent ions at concentrations above 50 mM inhibited the lipase activities in a concentration-dependent manner. Sodium dodecyl sulfate at a concentration lower than 10 mM completely inhibited the lipase activity.
authors.affiliation: Protein Engineering Section, National Research Council of Canada, Montreal.
authors.forename: K
authors.initials: K
authors.lastname: Veeraragavan
authors.forename: T
authors.initials: T
authors.lastname: Colpitts
authors.forename: B F
authors.initials: BF
authors.lastname: Gibbs
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002845:Chromatography; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D000431:Ethanol; D005848:Geotrichum / Q000201:enzymology*; D007525:Isoelectric Focusing; D008049:Lipase / Q000302:isolation & purification*; D003904:Mitosporic Fungi / Q000201:enzymology*; D008970:Molecular Weight
chemical_list: D000596:Amino Acids; D000431:Ethanol; D008049:Lipase