Screen Of Stereoselective Lactonization Lipase And Study On Lactonization

In this paper,strain for producing high lactonase activity and enantioselectivy with preference for the formation of the dextrogyrous biotin intermediate lactone was isolated from our laboratory.The strain was identified as Aspergillus oryzae WZ007.Lipase produced by Aspergillus oryzae WZ007 is an intracellular enzyme.We purified the lipase and studied the properties.The cell walls of the lipase was dissolved by lywallzyme,then purified by ammonium sulfate salting-out and High Q-catridge column anion- exchange chromatography.The optimum temperature of the purified lipase is 25?, and the optimum pH is 7.5.The molecular weight of the purified lipase is about 22.41KD.About 90%of the original activity is lost by heating at 80?for 10 minutes and 95%of the original activity is maintained by heating at 25?for 100 minutes.The enzyme activity is stimulated by Ca²⁺ and Mg²⁺,but is inhibited by Zn²⁺?Fe²⁺?Mn²⁺ and EDTA,K⁺ and Na⁺ have no influence on the enzyme activity. We explored the reaction system of lipase-stereoselective-catalyzed biotin intermediates.Such as lipase-stereoselective-catalyzed alcoholysis of biotin intermediate anhydride,lipase-stereoselective-catalyzed hydrolysis of biotin intermediate diester and lipase-stereoselective-catalyzed alcoholysis of racemic biotin intermediate.As a result,the routines of lipase-catalyzed desymmetriation of biotin intermediate lactone and biotin intermediate diester are available.