Gross D M, Barajas L
J Med. 1978;9(1):53-66.
Renin-containing granules isolated by isopycnic zonal centrifugation were partially characterized biochemically. Extracts of the granules were found to have a dual pH optimum at 5.5-6.0 and 7.0-7.5 and possess linear time-dependence of product formation when reacted with homologous renin substrate. Extracts also possessed a first order reaction constant of 0.713 X 10(-2). Treatment of the extracts with ammonium sulfate increased the velocity of the renin/renin substrate reaction though it continued to be linear with respect to time. This partially purified renin preparation was found to have a Km=3.9 X 10(3) ng/ml. Gel filtration of this preparation of renin demonstrated the presence of an active protein with renin activity and a molecular weight of 59,000 daltons in addition to an inactive protein of molecular weight 13, 750 daltons which may be a potential inhibitor of the renin/renin substrate reaction. The former protein or "big renin" may be the storage form or porhormone state of renin within the renin-containing granules of the juxtaglomerular cells.
通过等密度区带离心分离得到的含肾素颗粒进行了部分生化特性分析。发现颗粒提取物在pH 5.5 - 6.0和7.0 - 7.5时具有双重最适pH值，并且在与同源肾素底物反应时产物形成具有线性时间依赖性。提取物还具有0.713×10(-2)的一级反应常数。用硫酸铵处理提取物可提高肾素/肾素底物反应的速度，尽管其仍随时间呈线性关系。发现这种部分纯化的肾素制剂的Km = 3.9×10(3) ng/ml。对该肾素制剂进行凝胶过滤显示，除了分子量为13,750道尔顿的无活性蛋白（可能是肾素/肾素底物反应的潜在抑制剂）外，还存在一种具有肾素活性且分子量为59,000道尔顿的活性蛋白。前一种蛋白或“大肾素”可能是球旁细胞含肾素颗粒内肾素的储存形式或激素原状态。
