Oliver J A
Department of Medicine, Columbia University, College of Physicians and Surgeons, New York, New York 10032.
Hypertension. 1988 Jan;11(1):21-7. doi: 10.1161/01.hyp.11.1.21.
A procedure is described to isolate angiotensinogen (renin substrate) from canine plasma. The isolation procedure resulted in an 800-fold purification with a rate of recovery of approximately 12%. The purified protein has a specific activity of 24 micrograms of angiotensin I/mg protein. The amino terminal amino acid sequence of canine angiotensinogen was found to be identical to that of the horse but to differ from that of human and rat angiotensinogens. Canine angiotensinogen was heterogeneous with respect to molecular weight and isoelectric point. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of pure angiotensinogen revealed two closely spaced bands with apparent molecular weights of 58,000 and 56,000. Chromatofocusing showed four isoforms: Peaks of pure angiotensinogen eluted at pH levels of 4.32, 4.23, 4.15, and 4.04. Isoelectric focusing confirmed the presence of four isoforms. Thus, the purification procedure identified two molecular weight forms and four isoforms of canine angiotensinogen. Isolation of the four isoforms will allow their characterization and the study of their physiological significance.
本文描述了一种从犬血浆中分离血管紧张素原（肾素底物）的方法。该分离方法实现了800倍的纯化，回收率约为12%。纯化后的蛋白具有24微克血管紧张素I/毫克蛋白的比活性。犬血管紧张素原的氨基末端氨基酸序列与马的相同，但与人和大鼠的血管紧张素原不同。犬血管紧张素原在分子量和等电点方面具有异质性。纯血管紧张素原的十二烷基硫酸钠-聚丙烯酰胺凝胶电泳显示出两条紧密相邻的条带，表观分子量分别为58,000和56,000。色谱聚焦显示有四种同工型：纯血管紧张素原的峰在pH值4.32、4.23、4.15和4.04处洗脱。等电聚焦证实了四种同工型的存在。因此，纯化过程确定了犬血管紧张素原有两种分子量形式和四种同工型。分离这四种同工型将有助于对其进行表征并研究其生理意义。
