Fox P L, Zilversmit D B
Biochim Biophys Acta. 1982 Sep 14;712(3):605-15. doi: 10.1016/0005-2760(82)90289-2.
A microsomal system characterized by high flux through the entire de novo pathway from glycerol phosphate to phosphatidylcholine and triacylglycerol has been developed. Optimum synthesis of phosphatidylcholine requires CDPcholine, Mg2+, KCl and a palmitoyl-CoA-generating system containing palmitic acid, ATP and CoA. Incorporation of [14C]glycerol phosphate into phosphatidylcholine/triacylglycerol synthesis ratio decreases as palmitate is increased. Phosphatidylcholine synthesis from glycerol phosphate is stimulated more by palmitate than by other saturated fatty acids; phosphatidylcholine synthesis increases with increasing unsaturation of the added fatty acids. The ratio of incorporation of [3H]palmitate to [14C]glycerol phosphate was determined for phosphatidic acid, diacylglycerol, phosphatidylcholine and triacylglycerol. This ratio is approximately 2 for all diacylglycerolipids and 3 for triacylglycerol. In our system, incorporation of palmitate into microsomal glycerolipid proceeds primarily by the de novo pathway, with minimal fatty acid recycling via deacylation-reacylation.
已开发出一种微粒体系统，其特点是从磷酸甘油到磷脂酰胆碱和三酰甘油的整个从头合成途径具有高通量。磷脂酰胆碱的最佳合成需要CDP胆碱、Mg2+、KCl以及一个包含棕榈酸、ATP和辅酶A的棕榈酰辅酶A生成系统。随着棕榈酸含量的增加，[14C]磷酸甘油掺入磷脂酰胆碱/三酰甘油合成比率降低。与其他饱和脂肪酸相比，棕榈酸对由磷酸甘油合成磷脂酰胆碱的刺激作用更大；随着添加脂肪酸不饱和度的增加，磷脂酰胆碱的合成增加。测定了[3H]棕榈酸掺入磷脂酸、二酰甘油、磷脂酰胆碱和三酰甘油中与[14C]磷酸甘油的掺入比率。所有二酰甘油脂质的该比率约为2，三酰甘油的该比率为3。在我们的系统中，棕榈酸掺入微粒体甘油脂质主要通过从头合成途径进行，通过脱酰基-再酰化进行的脂肪酸循环最少。
