Morand O, Fibach E, Gatt S
Biochim Biophys Acta. 1982 Dec 8;693(1):143-50. doi: 10.1016/0005-2736(82)90480-1.
Radioactively-labelled palmitic acid was used to study the effects of albumin, low temperature and several inhibitors of metabolism on transport of fatty acids into cultured human leukemic myeloid cells. When serum or albumin were present in the medium, uptake of fatty acid by cells as well as its further incorporation into phospholipids and neutral lipids were considerably reduced. Uptake and metabolic utilization of this fatty acid was reduced at low temperature, in the presence or absence of albumin in the incubation medium. In absence of albumin, addition of iodoacetate, sodium cyanide or sodium azide had but little effect on the total uptake of fatty acids while metabolic utilization was reduced. When albumin was present, these inhibitors reduced both total uptake and incorporation into lipids. The data suggest that incorporation of the fatty acid into the outer layer of the cell membrane is controlled by the concentration of free, uncomplexed molecules of fatty acid adjacent to the cell surface. In the absence of albumin this is a fast reaction which reaches nearly maximal uptake in three minutes. In the presence of albumin, this process is much slower and follows a nearly linear course between 3 and 60 minutes. Translocation into the inner layer of the membrane and subsequent utilization for metabolic processes is a much slower process, which seems to depend on the quantity of the fatty acid in the outer layer.
放射性标记的棕榈酸被用于研究白蛋白、低温以及几种代谢抑制剂对脂肪酸转运进入培养的人白血病髓系细胞的影响。当培养基中存在血清或白蛋白时，细胞对脂肪酸的摄取以及其进一步掺入磷脂和中性脂质的过程均显著减少。在低温下，无论孵育培养基中是否存在白蛋白，这种脂肪酸的摄取和代谢利用都会降低。在无白蛋白的情况下，加入碘乙酸、氰化钠或叠氮化钠对脂肪酸的总摄取影响不大，但代谢利用会降低。当存在白蛋白时，这些抑制剂会降低总摄取以及脂质掺入。数据表明，脂肪酸掺入细胞膜外层受细胞表面相邻的游离、未复合脂肪酸分子浓度的控制。在无白蛋白的情况下，这是一个快速反应，三分钟内摄取几乎达到最大值。在有白蛋白的情况下，这个过程要慢得多，在3到60分钟之间几乎呈线性变化。转运到膜内层并随后用于代谢过程是一个慢得多的过程，这似乎取决于外层脂肪酸的量。
