ABSTRACT
Phosphatidate phosphohydrolase plays a central role in lipid metabolism in plants. Its importance in individual pathways in different plantsvaries but, in general, the diacylglycerol it produces is utilized both for membrane lipid formation and for storage triacylglycerol production. The demonstration of phosphatidate phosphohydrolase activity in subcellular fractions from plants was by Kates. The phosphatidate phosphohydrolase from mung bean cotyledons was localized in subcellular fractions prepared by isopycnic sucrose density separation of homogenates. Fractions rich in the acidic phosphatidate phosphohydrolase in mung bean also contained acidic p-nitrophenolphosphate activity. The low capacity of chloroplasts isolated from 18:3 plants to accumulate diacylglycerol, therefore, was a direct reflection that phosphatidate phosphohydrolase was poorly active. Phosphatidate had been presumed to be the precursor for diacylglycerol biosynthesis in fungi and yeasts and the presence of a phosphatidate phosphohydrolase has been demonstrated in two pathogenic dermatophytic fungi: Microsporum gypseum and Epidemophyton floccosum.
