Purification and characterization of two distinct lipases from Geotrichum candidum |
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Authors: | K Veeraragavan T Colpitts B F Gibbs |
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Affiliation: | Protein Engineering Section, National Research Council of Canada, Montreal. |
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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. |
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