ACYL GROUP TRANSFER FROM THE SN-1 POSITION OF PHOSPHOLIPIDS IN THE BIOSYNTHESIS OF N-DODECYL PALMITATE

The wax ester n-dodecyl palmitate is shown to be synthesized by retinal pigment epithelial membranes. The biosynthesis of this ester is phospholipid dependent and occurs via the transfer of a palmitoyl group from the sn-1 position of lecithin to n-dodecanol. When retinal pigment epithelial membranes are used as the source of enzyme, the apparent Michaelis constant for n-dodecanol in this process is 65.8 muM, and the maximal velocity for n-dodecyl palmitate synthesis is 16.2 nmol/(h.mg of protein). The enzymatic activity is membrane associated and shows a maximum velocity between pH 8 and pH 9. This transesterification process appears to be similar to the lecithin retinol acyl transferase reaction and is a further example of acyl group transfer reactions from the sn-1 position of phospholipids.