Partial purification and characterization of free and immobilized lipases fromMucor miehei.

Abstract

An extracellular lipase, a glycoprotein, produced by fermentation with a selected strain ofMucor miehei has been partially purified in two forms, A and B. The two forms have a high degree of antigenic identity and have similar pH-activity profiles with tributyroylglycerol as a substrate with optima at pH 7. They differ as follows: A, in contrast to B, requires activation at alkaline pH before analysis; A binds with concanavalin-A more completely than B; the net charges are slightly different at pH 8; and the isoelectric points are different. Our results indicate that the B lipase is formed by partial deglycosylation of the A lipase and that this influences the activity toward emulsions.In addition, the two enzymes have been immobilized by adsorption. These preparations and the soluble forms were highly specific for primary esters of triacylglycerols (TG); they usually hydrolyzed TG of 12∶0, 14∶0, 16∶0, and 18∶1 more rapidly than those of 4∶0, 6∶0, and 8∶0 and 10∶0 in mixtures of monoacid TG (4∶0 to 18∶1); and they were not stereospecific for TG. Immobilization altered the specificity of the preparations somewhat, in that slightly more 14∶0 and 16∶0 were released.