Inactivation of endothelin-1 by an enzyme of the vascular endothelial cells.
Inactivation of endothelin-1 by an enzyme of the vascular endothelial cells.
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血管内皮细胞酶使内皮素 1 失活。
DOI：
10.1161/01.hyp.21.6.925
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Erdös,EG
中科院分区：
文献类型：
--
作者：
Jackman,HL;Morris,PW;Rabito,SF;Johansson,GB;Skidgel,RA;Erdös,EG
我们先前研究了脱酰胺酶（溶酶体保护蛋白）对内皮素-1的失活，脱酰胺酶存在于许多细胞中，包括血管平滑肌细胞。我们最初从人血小板中纯化的这种酶优先水解在C-末端具有P1或P1'位置或两者的疏水氨基酸的肽，从而使内皮素-1失活，内皮素-1具有Ile 19-Ile 20-Trp 21-OH的C-末端序列。我们在培养的牛主动脉内皮细胞中检测了脱酰胺酶的存在。在pH 5.5和37 ℃下，均质化细胞的最终上清液（S3）以每10（6）个细胞1.3 nmol/min的速率裂解脱酰胺酶底物丹磺酰-Phe-Leu-Arg。内皮素-1被完全灭活的S3级分，大鼠胸主动脉条上确定。失活的主要位点是Ile 20-Trp 21键，通过高效液相色谱法和氨基酸分析确定，其中主要产物是des-Trp 21-内皮素-1。内皮素-1的水解（5.9 nmol/min每毫克蛋白质，pH 5.5，23 ℃）由S3主要由脱酰胺酶的抑制剂，包括二异丙基氟磷酸，但不是由一些其他肽酶的抑制剂。这是首次报道内皮细胞中内皮素-1代谢的新途径。因此，内皮细胞除了是内皮素-1的来源之外，还含有使其失活的酶。
We previously investigated the inactivation of endothelin-1 by deamidase (lysosomal protective protein), present in many cells, including vascular smooth muscle cells. This enzyme, which we originally purified from human platelets, preferentially hydrolyzes peptides at the C-terminus with hydrophobic amino acids in the P1 or P1' position or both and thereby inactivates endothelin-1, which has a C-terminal sequence of Ile19-Ile20-Trp21-OH. We tested for the presence of deamidase in cultured bovine aortic endothelial cells. The final supernatant of the homogenized cells (S3) cleaved the deamidase substrate dansyl-Phe-Leu-Arg at a rate of 1.3 nmol/min per 10(6) cells at pH 5.5 at 37 degrees C. Endothelin-1 was completely inactivated by the S3 fraction as determined on rat thoracic aorta strips. The major site of inactivation was the Ile20-Trp21 bond, established by high performance liquid chromatography and by amino acid analysis where the main product was des-Trp21-endothelin-1. The hydrolysis of endothelin-1 (5.9 nmol/min per milligram of protein at pH 5.5 at 23 degrees C) by S3 was blocked mainly by inhibitors of deamidase, including diisopropyl fluorophosphate, but not by inhibitors of some other peptidases. This is the first report of a novel pathway of endothelin-1 metabolism in endothelial cells. Thus, endothelial cells, besides being the source of endothelin-1, contain an enzyme that inactivates it.