Phosphatidylserine biosynthesis in cultured Chinese hamster ovary cells. I. Inhibition of de novo phosphatidylserine biosynthesis by exogenous phosphatidylserine and its efficient incorporation.

摘要: The effect of phosphatidylserine exogenously added to the medium on de novo biosynthesis was investigated in cultured Chinese hamster ovary cells. When cells were for several generations supplemented with and 32Pi, incorporation 32Pi into cellular remarkably inhibited, degree inhibition being dependent upon concentration phosphatidylserine. uptake phosphatidylethanolamine also partly reduced by addition exogenous phosphatidylserine, consistent idea that is biosynthesized via decarboxylation However, phosphatidylcholine, sphingomyelin, phosphatidylinositol not significantly affected. In contrast, either phosphatidylethanolamine, or did inhibit endogenous corresponding phospholipid. Radiochemical chemical analyses phospholipid composition revealed grown 80 microM almost entirely derived from Phosphatidylserine directly determined using [3H]serine-labeled Pulse pulse-chase experiments L-[U-14C] serine showed when rate synthesis 3-5-fold whereas turnover newly synthesized normal. Enzyme assaying extracts prepared without indicated appeared be caused a reduction level enzyme involved base-exchange reaction between phospholipids serine. These results demonstrate can efficiently incorporated utilized membrane biogenesis, thereby suppressed.