Matoba T, Murakami K, Inagami T
Biochim Biophys Acta. 1978 Oct 12;526(2):560-71. doi: 10.1016/0005-2744(78)90146-8.
In order to clarify the molecular basis of the unique features of rat renin (EC 3.4.99.19) and to provide materials and basic information for high blood pressure studies in rats, renin was purified from rat kidney. The final step of purification on CM-cellulose separated renin into three major isoenzyme peaks, R-I, R-II, R-III, and an additional minor peak. These preparations were judged homogeneous by multiple criteria, and the isoenzymes were found to have similar amino acid compositions. The amino acid composition is also closely analogous to hog renin, except that rat renin has a higher cysteine content. In contrast to hog renin, the rat enzymes do not contain amino sugars, yet are apparently glycoproteins as judged by their affinity for concanavalin A. The molecular weights of R-I, R-II, and R-III were estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 37 000, 36 000 and 35 000, respectively. The isoelectric points were 5.05, 5.15 and 5.22, respectively. The specific activities of the purified enzymes (determined using rat plasma as substrate) were 615, 626 and 452 Goldblatt units/mg, respectively. Comparison of activities with the hog- and rat-derived substrates indicated a preference for that from the rat. The reaction of the rat enzymes with a synthetic peptide substrate had a similar catalytic rate constant to the hog enzyme, indicating close similarity in the active site region of the two enzymes.
为了阐明大鼠肾素（EC 3.4.99.19）独特特性的分子基础，并为大鼠高血压研究提供材料和基础信息，从大鼠肾脏中纯化了肾素。在CM - 纤维素上的最后一步纯化将肾素分离为三个主要的同工酶峰，即R - I、R - II、R - III，以及一个额外的小峰。通过多种标准判断这些制剂是均一的，并且发现这些同工酶具有相似的氨基酸组成。氨基酸组成也与猪肾素非常相似，只是大鼠肾素的半胱氨酸含量更高。与猪肾素不同，大鼠的这些酶不含氨基糖，但根据它们与伴刀豆球蛋白A的亲和力判断显然是糖蛋白。通过十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳估计R - I、R - II和R - III的分子量分别为37000、36000和35000。其等电点分别为5.05、5.15和5.22。纯化酶的比活性（以大鼠血浆为底物测定）分别为615、626和452 Goldblatt单位/毫克。与猪源和大鼠源底物的活性比较表明，大鼠肾素更倾向于大鼠源底物。大鼠酶与合成肽底物的反应具有与猪酶相似的催化速率常数，表明这两种酶的活性位点区域非常相似。
