Purification and properties of prolylcarboxypeptidase (angiotensinase C) from human kidney.
Purification and properties of prolylcarboxypeptidase (angiotensinase C) from human kidney.
复制标题
人肾脯氨酰羧肽酶（血管紧张素酶 C）的纯化和特性。
DOI：
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发表时间：
1978
影响因子：
4.8
通讯作者：
E. G. Erdös
中科院分区：
文献类型：
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作者：
C. Odya;D. V. Marinkovic;K. Hammon;T. A. Stewart;E. G. Erdös
从人肾中纯化了脯氨酰羧肽酶，纯化倍数为1200倍，收率为18%。该酶没有组织蛋白酶A活性，在凝胶电泳中似乎是均一的。凝胶过滤法测得脯氨酰羧肽酶的分子量为115，000。在变性条件下，该酶解离成分子量为45，000和66，500的亚基。该酶以31 μ mol/h/mg蛋白质的速率裂解苄氧羰基（Cbz）-Pro-Phe（代表血管紧张素II和des-Asp 1-血管紧张素II（血管紧张素III）的COOH末端）。当N-保护的二肽中的苯丙氨酸被丙氨酸、缬氨酸或亮氨酸取代时，或者当八肽血管紧张素II或七肽血管紧张素III为底物时，水解速率增加。该酶还裂解血管紧张素II拮抗剂saralasin（Sar 1-Ala 8-血管紧张素II）。Cbz-Pro-Phe、血管紧张素II和血管紧张素III的Km值分别为1 mM、2 mM和0.77 mM。该酶具有酸性pH最适值（4.5至5.5），但在pH 7时水解血管紧张素III的最佳速率为50%。脯氨酰羧肽酶被二异丙基氟磷酸和胃酶抑素抑制，但不被螯合剂或-SH试剂。
Prolylcarboxypeptidase was purified from human kidney 1200-fold with 18% yield. The enzyme had no cathepsin A activity and appeared to be homogeneous in gel electrophoresis. The molecular weight of prolylcarboxypeptidase was estimated to be 115,000 by gel filtration. Under denaturing conditions the enzyme dissociated into subunits of 45,000 and 66,500 molecular weight. The enzyme cleaved benzyloxycarbonyl (Cbz)-Pro-Phe, representing the COOH-terminal end of angiotensin II and des-Asp1-angiotensin II (angiotensin III), at a rate of 31 micronmol/h/mg of protein. The rate of hydrolysis increased when phenylalanine in the N-protected dipeptide was replaced with alanine, valine, or leucine or when the octapeptide angiotensin II or the heptapeptide angiotensin III were the substrates. The enzyme also cleaved the angiotensin II antagonist saralasin (Sar1-Ala8-angiotensin II). The Km values were 1 mM, 2mM, and 0.77 mM with Cbz-Pro-Phe, angiotensin II, and angiotensin III, respectively. The enzyme had an acid pH optimum (4.5 to 5.5), but hydrolyzed angiotensin III at pH 7 at 50% of the optimal rate. Prolylcarboxypeptidase was inhibited by diisopropyl phosphorofluoridate and pepstatin, but not by sequestering agents or -SH reagents.