Conio G, Ghiani P, Patrone E, Trefiletti V, Uva B, Vallarino M
Biochim Biophys Acta. 1980 Jun 26;623(2):317-28. doi: 10.1016/0005-2795(80)90259-7.
Different forms of renin have been purified from bull kidney by combined gel filtration, affinity chromatography and ion-exchange chromatography. The specific activity of the enzyme was determined by a biochemical method of synthetic substrate and by radioimmunoassay on both synthetic and natural substrates; molecular characterization was carried out by molecular weight determinations, polyacrylamide gel electrophoresis, isoelectric focusing, amino acid analysis and optical rotatory dispersion. Three forms (renin C, D, E) are distinct on the basis of amino acid composition and chromatographic behavior, while possessing the same molecular weight, and displaying only minor differences in specific activity, alpha-helix content and isoelectric point; the occurrence of a group of renin isoenzymes may be suggested. Another form (A) has a lower specific activity and a higher molecular weight (57 000) compared with C, D and E and further differs markedly in chromatographic behavior, amino acid composition, alpha-helix content and isoelectric point, as well as in substrate specificity; it may be regarded as a pseudorenin. The fifth form (B) possesses the highest specific activity and does not correspond to a single molecular form; the presence of two components of different molecular weight (27 000 and 46 000 respectively) has been established both by polyacrylamide gel electrophoresis and isoelectric focusing.
通过凝胶过滤、亲和色谱和离子交换色谱相结合的方法，已从公牛肾脏中纯化出不同形式的肾素。采用合成底物的生化方法以及针对合成底物和天然底物的放射免疫分析法测定了该酶的比活性；通过分子量测定、聚丙烯酰胺凝胶电泳、等电聚焦、氨基酸分析和旋光色散进行了分子表征。三种形式（肾素C、D、E）在氨基酸组成和色谱行为上有所不同，但分子量相同，比活性、α-螺旋含量和等电点仅存在微小差异；由此推测可能存在一组肾素同工酶。另一种形式（A）与C、D和E相比，比活性较低，分子量较高（57 000），在色谱行为、氨基酸组成、α-螺旋含量和等电点以及底物特异性方面也有明显差异；它可能被视为一种假肾素。第五种形式（B）具有最高的比活性，且不对应单一分子形式；通过聚丙烯酰胺凝胶电泳和等电聚焦均已确定存在两种不同分子量的组分（分别为27 000和46 000）。
