GLYCOLIPID METABOLISM IN TUMOR AND TRANSFORMED CELLS

成瘤性与表达之间的可能关系 β-GalNAcT-1、β-GalNAcT-2和α-GalNAcT-3参与Gg-1和 LM 1中含Gb核心的鞘糖脂生物合成和SAT-3 生物合成将是这项研究计划的主要重点。 的 这项研究计划的总体直接目标是溶解和 从豚鼠肿瘤中纯化这三种N-乙酰氨基半乳糖转移酶 细胞（104 Cl和106 B）和鸡胚脑的阴离子交换， 特异性亲和层析。 的HPLC 125I-GSL（来自细胞表面） 和酶的研究也将进行比较的合成 豚鼠104 Cl生长周期中的Forssman抗原（糖脂） 和106 B培养的细胞。 放射性产品将被隔离， [14C-Ac]-GbOse 4Cer和[3与未标记的1H] GbOse 3Cer反应后 UDP-GalNAc。 末端GalNAc残基的确切化学键 将在纯化的酶产物的全甲基化后测定， 部分甲基化放射性的表征[3H]半乳糖 以及[14C-Ac]GalNAc单位。异构体键 将通过使用高度纯化的β-氨基己糖苷酶（刀豆 和番木瓜）和α-氨基己糖苷酶（蛤）。 纯化 来自蛤蜊的α-己糖胺酶也是该项目的一部分。 微分 这三种GalNAct活性的抑制作用将在 UDP、IDP、pCMB和NEM的存在。 唾液酸-新乳糖四糖基神经酰胺（LM 1）的体外生物合成 NeuAc-nLcOse 4Cer）在小鼠N-18克隆和人神经母细胞瘤1 MR-32中的表达 细胞将在拟议研究的第三年进行研究。 结合 的[125I]-标记的GSL、凝集素（Eunterus europeus）和毒素（霍乱 和蓖麻毒素）对神经母细胞瘤细胞表面的影响也将在此之前进行研究， 在用（But）化学诱导分化后，2 cAMP和HMBA。 （一）

Possible relationships between tumorigenicity and expression of beta-GalNAcT-1, beta-GalNAcT-2, and alpha-GalNAcT-3 involved in Gg-\and Gb-core-containing glycosphingolipid biosynthesis and SAT-3 in LM1 biosynthesis will be a major emphasis of this research proposal. The overall immediate objectives of this research program are to solubilize and purify these three N-acetylgalactosaminyltransferases from guinea pig tumor cells (104Cl and 106B) and embryonic chicken brains by anion exchange and specific affinity chromatography. HPLC of 125I-GSLs (from cell surfaces) and enzymatic studies will also be carried out to compare the synthesis of Forssman antigen (glycolipid) during the growth cycle of guinea pig 104Cl and 106B cultured cells. Radioactive products will be isolated from [14C-Ac]-GbOse4Cer and [3H]GbOse3Cer after reaction with unlabeled UDP-GalNAc. The exact chemical linkages of the terminal GalNAc residues will be determined after permethylation of purified enzymatic products and characterization of the partially methylated radioactive [3H]galactose and [14C-Ac]GalNAc units obtained by autoradiography. Anomeric linkages will be determined by using highly purified beta-hexosaminidase (jack bean and papaya) and alpha-hexosaminidase (clam). Purification of alpha-hexosaminidase from clam is also part of this project. Differential inhibition of these three GalNAct activities will be studied in the presence of UDP, IDP, pCMB, and NEM. Biosynthesis in vitro of LM1 (sialosyl-neolactotetraosylceramide; NeuAc-nLcOse4Cer) in mouse N-18 clone and in human neuroblastoma 1MR-32 cells will be investigated in the third year of proposed research. Binding of [125I]-labeled GSLs, lectin (Eunonymus europeus) and toxins (cholera and ricin) to neuroblastoma cell surfaces will also be studied before and after chemically induced differentiation with (But)2 cAMP and HMBA. (A)