Biosynthetic and Immunochemical Investigation of Sulfated Glycosaminoglycans

该项目的长期目标是阐明在所谓的共同碳水化合物-蛋白质连接结构GlcA β 1- 3gal β 1- 3gal β 1- 4xyl β 1- o- ser上合成不同硫酸化糖胺聚糖的生物合成机制。我们对各种蛋白聚糖的糖-蛋白连锁区进行了结构研究，并对各种糖胺聚糖磺基转移酶的调控机制进行了酶学研究，得到了以下结果：在之前的研究中，我们在群鼠软骨肉瘤的4-硫酸软骨素蛋白聚糖的糖-蛋白连锁区发现了新的结构Gal(4-O-sulfate)beta1-3Gal beta1-4Xyl。在本研究中，我们在鲸鱼软骨中也发现了这种结构。我们在鲨鱼软骨的软骨素6-硫酸盐蛋白聚糖的糖-蛋白连接区发现了另一个新的结构，Gal - β - 3gal (6-O-sulfate) β - 4xyl。上述两个新结构在肝素中未发现，提示它们是硫酸软骨素特异性的。我们从恩格尔布雷特-霍尔姆-蜂群小鼠肿瘤的杂交蛋白聚糖中分离出含有过硫酸乙酰肝素和过硫酸半乳糖胺聚糖的肽聚糖。过硫酸盐半乳糖胺聚糖含有新的GalNAc 4,6-二磺酸结构。结果表明，不同的磺化糖胺聚糖均可抑制软骨素（GalNAc）6-O-磺基转移酶、硫酸肝素（GlcNH_2）2- n -磺基转移酶和硫酸角蛋白（Gal）6-O-磺基转移酶的活性，而前者可被多胺和含聚赖氨酸片段的c-Ki-ras 2蛋白碱性肽激活。

The long term objective of this project is to clarify the biosynthetic mechanisms by which different sulfated glycosaminoglycans are synthesized on the so-called common carbohydrate-protein linkage structure, GlcA beta1-3Gal beta1-3Gal beta1-4Xyl beta1-O-Ser. We performed the structural studies of the carbohydrate-protein linkage region of various proteoglycans and the enzymological studies of the regulatory mechanisms of various glycosaminoglycan sulfotransferases and obtained the following results.1. In the previous study we discovered the new structure, Gal(4-O-sulfate)beta1-3Gal beta1-4Xyl, in the carbohydrate-protein linkage region of chondroitin 4-sulfate proteoglycans from Swarm rat chondrosarcoma. In the present study we found this structure also in whale cartilage chondroitin 4-sulfate.2. We discovered another new structure, Gal beta1-3Gal(6-O-sulfate)beta1-4Xyl, in the carbohydrate-protein linkage region of chondroitin 6-sulfate proteoglycans of shark cartilage.3. The above two new structures could not be found in heparin, suggesting that they are specific to chondroitin sulfate.4. We isolated the peptidoglycans bearing both undersulfated heparan sulfate and oversulfated galactosaminoglycans derived from hybrid proteoglycans of Engelbreth-Holm-Swarm mouse tumor. The oversulfated galactosaminoglycans contained the novel GalNAc 4,6-disulfated structure.5. We found that chondroitin (internal GalNAc)6-O-sulfotransferase, heparan sulfate (GlcNH_2)2-N-sulfotransferase, keratan sulfate (Gal)6-O- sulfotransferase activities were inhibited by various sulfated glycosaminoglycans, and that the former enzymes were activated by polyamines and basic peptides including polylysine-containing segment of c-Ki-ras 2 protein.