Burgoyne R D, Morgan A
Department of Physiology, University of Liverpool, England.
FEBS Lett. 1989 Mar 13;245(1-2):122-6. doi: 10.1016/0014-5793(89)80204-2.
Adrenal medullary homogenates and chromaffin granule membranes were separated by SDS-polyacrylamide gel electrophoresis and GTP-binding proteins detected using [alpha-32P]GTP binding to nitrocellulose blots. Four GTP-binding polypeptides of 24, 22, 20 and 18 kDa were routinely found in medullary homogenates and all were also found in isolated chromaffin granule membranes. The GTP-binding polypeptides co-sedimented with granule membrane markers following separation on sucrose gradients. On the basis of trypsin sensitivity and resistance to extraction, the GTP-binding proteins appeared to be tightly bound to the cytoplasmic surface of the granules. One or more of the secretory granule GTP-binding proteins could be involved in exocytosis in adrenal chromaffin cells.
肾上腺髓质匀浆和嗜铬颗粒膜通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分离，并用[α-32P]GTP结合硝酸纤维素印迹法检测GTP结合蛋白。在髓质匀浆中通常可发现四种分子量分别为24、22、20和18 kDa的GTP结合多肽，在分离的嗜铬颗粒膜中也均能找到。在蔗糖梯度上分离后，这些GTP结合多肽与颗粒膜标记物共同沉降。基于对胰蛋白酶的敏感性和对提取的抗性，这些GTP结合蛋白似乎紧密结合在颗粒的细胞质表面。一种或多种分泌颗粒GTP结合蛋白可能参与肾上腺嗜铬细胞的胞吐作用。
