Lafeber F P, Hanssen R G, Choy Y M, Flik G, Herrmann-Erlee M P, Pang P K, Bonga S E
Department of Animal Physiology, Faculty of Science, University of Nijmegen, The Netherlands.
Gen Comp Endocrinol. 1988 Jan;69(1):19-30. doi: 10.1016/0016-6480(88)90048-2.
We have isolated and purified a glycoprotein from the corpuscles of Stannius (CS) of trout, which we consider hypocalcin (also called teleocalcin), the major hypocalcemic hormone of fish. This product is present in relatively large amounts in the CS of several species (i.e., European eel, tilapia, goldfish, and carp). Hypocalcin is typically released from the CS in response to an experimentally induced increase of the blood calcium concentration. Ultrastructural observations show that after this treatment the type 1 cells, reportedly the hypocalcin-producing cell type of the CS, are almost completely degranulated. The isolated glycoprotein has an apparent molecular weight of 54 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This molecule appears susceptible to breakdown and is recovered upon concanavalin-A affinity chromatography as a 41 kDa product. Reducing agents such as mercaptoethanol or dithiothreitol employed, e.g., during standard electrophoretic techniques or during amino acid sequence analysis, allow only the recovery of 28 or 18 kDa products. Evidence is given that the 54 and 41 kDa products are dimer molecules, with the 28 and 18 kDa products as their respective monomeric constituents. The sequence of the first 33 N-terminal amino acids of these products and the composition of the sugar component are presented.
我们从鳟鱼的斯坦尼斯小体（CS）中分离并纯化了一种糖蛋白，我们认为它是降钙素（也称为远距降钙素），是鱼类主要的降血钙激素。该产物在几种物种（即欧洲鳗鲡、罗非鱼、金鱼和鲤鱼）的CS中含量相对较高。降钙素通常在实验诱导的血钙浓度升高时从CS中释放。超微结构观察表明，经过这种处理后，据报道CS中产生降钙素的1型细胞几乎完全脱颗粒。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳测定，分离出的糖蛋白的表观分子量为54 kDa。该分子似乎易于分解，在伴刀豆球蛋白A亲和层析中作为41 kDa的产物回收。例如，在标准电泳技术或氨基酸序列分析过程中使用的巯基乙醇或二硫苏糖醇等还原剂，只能回收28 kDa或18 kDa的产物。有证据表明，54 kDa和41 kDa的产物是二聚体分子，28 kDa和18 kDa的产物分别是它们的单体成分。给出了这些产物前33个N端氨基酸的序列和糖成分的组成。
