Scheffer R C, Poort C, Slot J W
Eur J Cell Biol. 1980 Dec;23(1):122-8.
A glycoprotein resembling the major zymogen granules membrane-associated glycoprotein (GP-2) from the exocrine rat pancreas was detected in a 200 000 g sedimentable subfraction from pancreatic secretion. This glycoprotein had a slightly smaller molecular weight than GP-2 (70 000 D versus 75 000 D), gave a line of identity with GP-2 in a double immunodiffusion test against anti GP-2, and tryptic peptide charts of both glycoproteins were largely similar. Immunofluorescence cytochemistry showed that GP-2 antigens were exclusively located in the exocrine pancreas, where they were preferentially found in the perimeter of secretory granules and in the acinar lumina. These results suggest the possibility of loss of GP-2 from exocrine cells during secretion and raise doubts as to the status of GP-2 as a true membrane glycoprotein.
在大鼠胰腺分泌液经200000g离心得到的可沉降亚组分中，检测到一种类似于大鼠外分泌胰腺主要酶原颗粒膜相关糖蛋白（GP-2）的糖蛋白。该糖蛋白的分子量略小于GP-2（分别为70000D和75000D），在与抗GP-2的双向免疫扩散试验中与GP-2呈现一条同一性沉淀线，且两种糖蛋白的胰蛋白酶肽图基本相似。免疫荧光细胞化学显示，GP-2抗原仅位于外分泌胰腺中，在分泌颗粒周边和腺泡腔内优先发现。这些结果提示，分泌过程中外分泌细胞可能会丢失GP-2，并对GP-2作为一种真正的膜糖蛋白的地位提出了质疑。
