FIGURE 4.
LDs contain LPCAT activity. A, lysates of HuH7, COS7, and A431 cells as indicated, cultured in the presence of 100 μm oleic acid, were subjected to floatation in a sucrose density gradient. Lysates (lysate) or purified LDs (LD) were incubated in the presence of [3H]acyl-CoA and lysophosphatidylcholine (LPC) or lysophosphatidic acid (LPA). Lipids were extracted and analyzed by TLC followed by autoradiography. Radioactive spots were identified by co-migrating standards; PC, phosphatidylcholine; PA, phosphatidic acid. B, table shows the enrichment of LPCAT activity on LDs relative to LPAAT or glucose-6-phosphatase activity, defined as the ratio of LPCAT/LPAAT activities or LPCAT/Glc-6-Pase activities in the LDs, divided by the same ratio in the lysates.