KINETIC PROPERTIES OF PHOSPHATIDYLINOSITOL SYNTHASE FROM GERMINATING SOYBEANS

CDP-1,2-diacyl-sn-glycerol (CDP-diacylglycerol): myo-inositol phosphatidyltransferase (EC. 2.7.8.11) catalyzes the final step in the de novo synthesis of phosphatidylinositol in the microsome fraction of germinating soybeans. The Michaelis constants for CDP-diacylglycerol and myo-inositol were determined for the reaction using a Triton X-100-CDP-diacylglycerol mixed micelle substrate. The Kmvalues for CDP-diacylglycerol and myo-inositol were 30μM and 0.11 mM, respectively.