Stone G C, Hammerschlag R
J Neurochem. 1983 Apr;40(4):1124-33. doi: 10.1111/j.1471-4159.1983.tb08103.x.
The role carbohydrate residues may play in the sorting of newly synthesized fast-transported proteins during the initiation of fast axonal transport has been examined by identifying individual fast-transported glycoproteins that contain either or both fucose and galactose. [3H]Fucose or [3H]galactose was incorporated together with [35S]methionine in vitro in bullfrog dorsal root ganglia. Fast-transported proteins that accumulated proximal to a ligature on the spinal nerve were separated via two-dimensional gel electrophoresis, and 92 gel spots were analyzed quantitatively for the presence of 35S and 3H. Of these spots, 56 (61%) contained either or both fucose and galactose. Glycomoieties were generally associated with families of charged spots whose isoelectric points could be altered with neuraminidase treatment. Single spots tended to be unglycosylated and were unaffected by neuraminidase. The prevalence of glycoproteins was considerably greater in the higher-molecular weight range. Of the 55 spots analyzed with molecular weight greater than approximately 35,000 daltons, 89% were glycosylated, whereas only 19% of the 37 spots with lower molecular weight contained sugar moieties. When considered in light of previous studies in which similar subpopulations have been described, the current findings suggest that the presence or absence of glycomoieties may represent another criterion by which proteins are sorted during the initiation of fast axonal transport.
通过鉴定含有岩藻糖和半乳糖其中之一或两者的单个快速运输糖蛋白，研究了碳水化合物残基在快速轴突运输起始过程中对新合成的快速运输蛋白分选可能发挥的作用。[3H]岩藻糖或[3H]半乳糖与[35S]甲硫氨酸一起在牛蛙背根神经节中进行体外掺入。通过二维凝胶电泳分离在脊神经结扎近端积累的快速运输蛋白，并对92个凝胶斑点进行35S和3H存在情况的定量分析。在这些斑点中，56个（61%）含有岩藻糖和半乳糖其中之一或两者。糖基部分通常与带电斑点家族相关，其等电点可通过神经氨酸酶处理而改变。单个斑点往往未糖基化且不受神经氨酸酶影响。糖蛋白在较高分子量范围内的比例相当高。在分析的55个分子量大于约35,000道尔顿的斑点中，89%被糖基化，而在37个分子量较低的斑点中只有19%含有糖基部分。结合先前描述过类似亚群的研究来看，当前的研究结果表明，糖基部分的存在与否可能代表了在快速轴突运输起始过程中对蛋白质进行分选的另一个标准。
