Bousso-Mittler D, Galron R, Sokolovsky M
Department of Biochemistry, George S. Wise Faculty of Life Science, Tel Aviv University, Israel.
Biochem Biophys Res Commun. 1991 Aug 15;178(3):921-6. doi: 10.1016/0006-291x(91)90979-h.
Neuraminidase was used in an attempt to determine whether the endothelin (ET)/sarafotoxin (SRTX) receptor subtypes are glycoproteins and, if so, to determine the role of the carbohydrate moiety in the binding of ligands to the receptor. Incubation of rat cerebellar membranes with neuraminidase was accompanied by a decrease in the capacity of the receptors to bind ET-1 and SRTX-b. In contrast, treatment of the rat caudate putamen and strium or of guinea pig ileum with the enzyme did not affect the binding properties of these receptors. Following exposure of [125I]-ET-1 affinity-labeled receptor to neuraminidase, gel electrophoresis and autoradiography revealed a decrease in molecular mass in the cerebellar and atrial preparations of about 2.5-2.8 kDa. These data indicate that some of the ET/SRTX receptors are glycoproteins and that the sugar moiety is important for ligand binding. Thus, glycosylation might be responsible for the observed heterogeneity among ET/SRTX receptors.
使用神经氨酸酶来试图确定内皮素（ET）/铃蟾毒素（SRTX）受体亚型是否为糖蛋白，若如此，则确定碳水化合物部分在配体与受体结合中的作用。用神经氨酸酶孵育大鼠小脑膜后，受体结合ET-1和SRTX-b的能力下降。相反，用该酶处理大鼠尾状核壳核和纹状体或豚鼠回肠，并不影响这些受体的结合特性。将[125I]-ET-1亲和标记的受体暴露于神经氨酸酶后，凝胶电泳和放射自显影显示，小脑和心房制剂中的分子量下降了约2.5 - 2.8 kDa。这些数据表明，一些ET/SRTX受体是糖蛋白，并且糖部分对于配体结合很重要。因此，糖基化可能是导致ET/SRTX受体间观察到的异质性的原因。
