Suga K, Ito K, Tsuru D, Yoshimoto T
School of Pharmaceutical Sciences, Nagasaki University, Japan.
Biosci Biotechnol Biochem. 1995 Feb;59(2):298-301. doi: 10.1271/bbb.59.298.
Prolylcarboxypeptidase (Angiotensinase C, EC 3.4.16.2) was purified to homogeneity from cell free extracts of Xanthomonas maltophilia by ammonium sulfate fractionation and sequential chromatographies on DEAE-Toyopearl, Sephadex G-150, FPLC-Hiload Superdex 200 pg, and FPLC-Hitrap SP columns, with an activity recovery of 15%. The molecular weight of the enzyme was found to be 330,000 by gel filtration and 83,000 by SDS-PAGE, suggesting a tetrameric form for the native enzyme. It had an optimum pH of 8.5 and stability between pH 8.0 and 11.0. The isoelectric point of the enzyme was 6.6. The enzyme hydrolyzed Pro-X bonds when proline was in the penultimate position from the carboxyl terminal. The enzyme was strongly inhibited by diisopropylfluorophosphate (DFP), while phenylmethylsulfonyl fluoride (PMSF), p-chloromercuribenzoic acid (PCMB), iodoacetamide, and metal chelators had no effect.
脯氨酰羧肽酶（血管紧张素酶C，EC 3.4.16.2）通过硫酸铵分级分离以及在DEAE - Toyopearl、Sephadex G - 150、FPLC - Hiload Superdex 200 pg和FPLC - Hitrap SP柱上的连续层析，从嗜麦芽窄食单胞菌的无细胞提取物中纯化至同质，活性回收率为15%。通过凝胶过滤法测得该酶的分子量为330,000，通过SDS - PAGE测得为83,000，表明天然酶为四聚体形式。其最适pH为8.5，在pH 8.0至11.0之间稳定。该酶的等电点为6.6。当脯氨酸位于羧基末端的倒数第二位时，该酶可水解脯氨酸 - X键。该酶受到二异丙基氟磷酸（DFP）的强烈抑制，而苯甲基磺酰氟（PMSF）、对氯汞苯甲酸（PCMB）、碘乙酰胺和金属螯合剂则无影响。
