Figure 3.

Effects of possible substrates on DGTS synthesis. A, The effects of increasing SAM concentrations on DGTS synthesis. Carboxyl-radiolabeled SAM was used and the radioactivity in the DGTS spot determined after chromatography. The apparent K_m was estimated to be 74 μm and the V_max to be about 250 μm. B, Results on DGTS synthesis by the microsomal fraction resulting from increasing concentrations of a possible lipid precursor, diacylglycerol (DAG). Egg DAG, derived from egg PtdCho, was added as a naturally occurring mixture of DAG species. DAG-16:0, 18:1 is a possible natural precursor of DGTS synthesis.