GLYCOLIPID METABOLISM IN NORMAL AND PATHOLOGICAL TISSUES

拟议的研究的直接目标是四个方面：l。 11日龄猪β GalT-4和SAT-3的纯化及动力学研究 鸡胚脑。 2. 纯化和底物特异性 使用AlphaFucT-2（GDP-Fuc：nLcOse 4Cer（al-2）岩藻糖基转移酶）的研究， 牛脾 3. 的体外生物合成及结构测定 二唾液酸乳糖四糖神经酰胺（NeuAc-NeuGc-Gal-GlcNAc-Gal-Glc-Cer）和 牛乳糖-N-降己糖神经酰胺（Gal-GlcNac-Gal-GlcNac-Gal-Glc-Cer） 脾脏高尔基体丰富的膜部分。 这些产品的前体已被 从我们实验室的牛红细胞中分离并表征。 4. 在本调查的最后阶段，将尝试比较 糖脂：糖基转移酶活性（β GalT-3， β GalT-4和SAT-3）在培养的泰-萨克斯病细胞（转化的 和未转化的）和来源于Tay-Sachs的亚细胞级分中 病脑（死后）。 除了缺乏溶酶体外， 氨基己糖苷酶A与Tay-Sachs脑中GM 2神经节苷脂的积累 可能是合成酶严重缺乏的结果 BetaGalT-3（UDP-Gal：Gm 2（Beta1-3）半乳糖基转移酶），建议 我们的初步工作。 (The鞘糖脂：糖基转移酶 简称GSLTs）。 目前的研究关注的是 神经节苷脂和血型相关鞘糖脂的生物合成 正常组织（鸡胚脑和牛脾）和 病理性人脑（死后组织）。 我们的总体目标是 研究的目的是加深对GSLTs特性的理解。

Immediate objectives of the proposed research are fourfold: l. Purification and kinetic studies of BetaGalT-4 and SAT-3 from 11-day-old embryonic chicken brains. 2. Purification and substrate specificity studies with AlphaFucT-2 (GDP-Fuc:nLcOse4Cer(al-2)fucosyltransferase) from bovine spleen. 3. Biosynthesis in vitro and structure determination of disialoneolactotetraosylceramide(NeuAc-NeuGc-Gal-GlcNAc-Gal-Glc-Cer) and lacto-N-norhexaosylceramide(Gal-GlcNac-Gal-GlcNac-Gal-Glc-Cer) in bovine spleen Golgi-rich membrane fraction. Precursor of these products have been isolated and characterized from bovine erythrocytes in our laboratory. 4. In the final states of this investigation attempts will be made to compare the levels of glycolipid:glycosyltransferase activities (BetaGalT-3, BetaGalT-4, and SAT-3) in cultured Tay-Sachs diseased cells (Transformed and nontransformed) and in the subcellular fractions derived from Tay-Sachs diseased brains (post-mortem). In addition to the absence of lysosomal hexosaminidase A the accumulation of GM2 ganglioside in Tay-Sachs brains could be the result of a severe deficiency of the synthetic enzyme BetaGalT-3 (UDP-Gal:Gm2(Beta1-3)galactosyltransferase), which is suggested from our preliminary work. (The glycosphingolipid: glycosyltransferases are abbreviated as GSLTs). Present studies are concerned with the biosynthesis of gangliosides and blood group-related glycosphingolipids in normal tissues (embryonic chicken brains and bovine spleen) and pathological human brains (post-mortem tissues). The overall goal of our research is to develop an understanding of the specificities of GSLTs.