DOI link for General Introduction
General Introduction book
The phosphatidate can be converted to diacylglycerol through the action of phosphatidate phosphohydrolas. Phosphatidate can be produced de novo from either glycerol phosphate or dihydroxyacetone phosphate. There appears to be at least three different acyltransferases that initiate this synthesis. The first is a glycerol phosphate acyltransferase that is located in the endoplasmic reticulum on the cytosolic surface. A second glycerol phosphate acyltransferase is located on the outer mitochondrial membrane. A third acyltransferase is found mainly in peroxisomes and this enzyme esterifies dihydroxyacetone phosphate and not glycerol phosphate. The activity of lysophosphatidate acyltransferase is normally relatively low in mitochondrial compared with microsomal fractions. Potentially, phosphatidate phosphohydrolase could act upon phosphatidate that is produced de novo in mitochondria or in the endoplasmic reticulum. Most of the original methods for the measurement of phosphatidate phosphohydrolase activity relied upon the determination of the release of inorganic phosphate from phosphatidate emulsions.