Yamada K, Abe A, Sasaki T
J Biol Chem. 1985 Apr 25;260(8):4615-21.
Lipid specificity has been studied in the lipid transfer reaction facilitated by the glycolipid transfer protein from pig brain. The lipid transfer was measured by determining the transfer of a radioisotopically labeled lipid from donor liposomes to either acceptor liposomes or mitochondria. Whenever possible, the liposomes contained 1 mol % of the lipid whose transfer was under study. The transfer protein accelerates the transfer of glucosylceramide, galactosylceramide (GalCer), lactosylceramide (LacCer), galactosylceramide 3-sulfate, globotriaosylceramide, LacCer sulfate, sialosyl-LacCer, globotetraosylceramide, and globopentaosylceramide. An inverse relationship is found between the length of sugar chains in glycosphingolipids and the transfer rates. In addition to the glycosphingolipids, the transfer protein facilitates the transfer of galactosyldiacylglycerol, digalactosyldiacylglycerol, glucosyldiacylglycerol, and diglucosyldiacylglycerol. The protein does not facilitate the transfer of dimannosyldiacylglycerol. The transfer of periodate-oxidized and subsequently reduced derivatives of GalCer and LacCer is facilitated by the transfer protein. The derivatives of GalCer are transferred at lower rates than GalCer, whereas the derivatives of LacCer are transferred at higher rates than LacCer. The transfer protein does not facilitate the transfer of phosphatidylcholine, phosphatidylinositol, cholesterol, or cholesteryloleate. These results suggest that the glycolipid transfer protein from pig brain has specificity to hydroxyl groups present in the sugar residue directly linked to either ceramide or diacylglycerol. The presence of glucose or galactose linked to these hydrophobic moieties makes the glycolipid transferable by the protein.
已对猪脑糖脂转移蛋白促进的脂质转移反应中的脂质特异性进行了研究。通过测定放射性同位素标记的脂质从供体脂质体向受体脂质体或线粒体的转移来测量脂质转移。只要有可能，脂质体就含有1摩尔%正在研究其转移的脂质。转移蛋白可加速葡萄糖神经酰胺、半乳糖神经酰胺（GalCer）、乳糖神经酰胺（LacCer）、硫酸半乳糖神经酰胺、球三糖神经酰胺、硫酸LacCer（LacCer sulfate）、唾液酸-LacCer（sialosyl-LacCer）、球四糖神经酰胺和球五糖神经酰胺的转移。发现鞘糖脂中糖链长度与转移速率之间呈反比关系。除了鞘糖脂外，转移蛋白还促进半乳糖基二酰基甘油、二半乳糖基二酰基甘油、葡萄糖基二酰基甘油和二葡萄糖基二酰基甘油的转移。该蛋白不促进二甘露糖基二酰基甘油的转移。转移蛋白促进GalCer和LacCer经高碘酸盐氧化并随后还原的衍生物的转移。GalCer的衍生物转移速率低于GalCer，而LacCer的衍生物转移速率高于LacCer。转移蛋白不促进磷脂酰胆碱、磷脂酰肌醇、胆固醇或胆固醇油酸酯的转移。这些结果表明，猪脑糖脂转移蛋白对直接与神经酰胺或二酰基甘油相连的糖残基中存在的羟基具有特异性。与这些疏水部分相连的葡萄糖或半乳糖的存在使得糖脂能够被该蛋白转移。
