Selectivity for Incorporation of n-3 and n-6 Unsaturated Fatty Acids into Phospholipids

通过改变培养液中n-3不饱和脂肪酸与n-6不饱和脂肪酸的比例，研究了n-3和n-6不饱和脂肪酸对细胞磷脂的选择性掺入。不饱和程度较低的不饱和脂肪酸可以独立于n-3和n-6而大量并入磷脂酰胆碱。不饱和程度较高的不饱和脂肪酸主要与磷脂酰乙醇胺结合。当不饱和脂肪酸之间的双键数相差大于2时。不饱和程度高的不饱和脂肪酸比不饱和程度低的不饱和脂肪酸更有选择性地掺入磷脂酰乙醇胺。通过分子种类分析。不饱和程度较高的N-3和n-6不饱和脂肪酸竞争性掺入到磷脂酰乙醇胺中。最后，二十二碳六烯酸比其他不饱和脂肪酸更有选择性地掺入二酰基磷脂酰乙醇胺。此外。线粒体、内质网和质膜的磷脂酰胆碱和磷脂酰乙醇胺具有相似的选择性，与细胞器的差异无关。

The selective incorporation of n-3 and n-6 unsaturated fatty acids into cell phospholipids was investigated by changing the ratio of n-3 unsaturated fatty acids against n-6 unsaturated fatty acids in the medium where Chinese hamster V79-R cells were grown. Unsaturated fatty acids with lower degrees of unsaturation were abundantly incorporated into phosphatidylcholine independently of n-3 and n-6. Unsaturated fatty acids with highter degrees of unsaturation were more predominantly incorporated into phosphatidylethanolamine. When the difference in the number of double bond between unsaturated fatty acids was more than two. the unsaturated fatty acids with a higher degree of unsaturation was more selectively incorporated into phosphatidylethanolamine than the unsaturated fatty acids with a lower dgree of unsaturation. By the analysis of molecular species. n-3 and n-6 unsaturated fatty acids with higher degrees of unsaturation were incorporated competitively into phosphatidylethanolamine. Finally, docosahexaenoic acid was incorporated into diacyl phosphatidylethanolamine more selectively than the other unsaturaed fatty acids.In addition. the similar selectivity was found in phosphatidylcholine and phosphatidylethanolamine of mitochondria, endoplasmic reticulum and plasma membrane, independent of the difference among organelles.