Day R P, Luetscher J A
J Clin Endocrinol Metab. 1975 Jun;40(6):1085-93. doi: 10.1210/jcem-40-6-1085.
The properties of big renin, a relatively inactive form of renin isolated from human plasma, were examined following partial purification by gel filtration. Exposure of big renin to pH 3.0-3.6, or brief incubation with trypsin or pepsin, resulted in a ten-fold increase in enzymatic activity. Activation was not effected by 4M NaCl, 6M urea, or incubation with neuraminidase. Both before and after inactivation, big renin eluted from Sephadex gel more rapidly than normal plasma renin. During polyacrylamide gel disc electrophoresis, inactive big renin migrated more slowly than either normal renin or big renin previously activated. Using sheep substrate, the enzyme kinetics of normal renin and previously activated big renin were identical, while inactive big renin possessed a higher Michaelis constant. These data indicate that big renin is closely related biochemically to normal plasma renin. As the activation of big renin results in the formation of the substance even more similar to normal renin, the possibility exists that big renin may prove to be a precursor form of normal renin.
从人血浆中分离出的相对无活性的肾素形式——大分子肾素，在经凝胶过滤部分纯化后，对其性质进行了研究。将大分子肾素暴露于pH 3.0 - 3.6，或与胰蛋白酶或胃蛋白酶短暂孵育，会导致酶活性增加十倍。4M氯化钠、6M尿素或与神经氨酸酶孵育均不会影响其激活。在失活前后，大分子肾素从葡聚糖凝胶上洗脱的速度都比正常血浆肾素更快。在聚丙烯酰胺凝胶圆盘电泳过程中，无活性的大分子肾素迁移速度比正常肾素或先前激活的大分子肾素都要慢。使用绵羊底物时，正常肾素和先前激活的大分子肾素的酶动力学相同，而无活性的大分子肾素具有更高的米氏常数。这些数据表明，大分子肾素在生化性质上与正常血浆肾素密切相关。由于大分子肾素的激活会导致形成与正常肾素更相似的物质，因此大分子肾素可能是正常肾素的前体形式。
