Wu-Wong J R, Budzik G P, Devine E M, Opgenorth T J
Pharmaceutical Products Division, Abbott Laboratories, Abbott Park, IL 60064.
Biochem Biophys Res Commun. 1990 Sep 28;171(3):1291-6. doi: 10.1016/0006-291x(90)90826-9.
An enzyme activity which converts human big endothelin (1-38) to endothelin (1-21) and a C-terminal fragment (CTF, 22-38) was identified in a plasma membrane fraction prepared from rat lung. The conversion activity was optimal at pH 4.0, was inhibited by Pepstatin-A (IC50 = 20 nM), but was not affected by TLCK, Aprotinin, PMSF, E-64, Bestatin, Phosphoramidon or Thiorphan at 40 microM. Metal ions activated the activity by 1.5 - 2.5 fold in the order of Mn+2 greater than Zn+2 = Ca+2 greater than Ba+2. These data suggest that a Pepstatin-A inhibitable, metal ion related aspartic protease may be involved in the conversion of big endothelin to endothelin in rat lung.
在从大鼠肺制备的质膜组分中鉴定出一种将人 big 内皮素（1 - 38）转化为内皮素（1 - 21）和 C 末端片段（CTF，22 - 38）的酶活性。该转化活性在 pH 4.0 时最佳，被胃蛋白酶抑制剂 A（IC50 = 20 nM）抑制，但在 40 μM 时不受 TLCK、抑肽酶、苯甲基磺酰氟、E - 64、贝抑素、磷酰胺脒或硫磷酰胺的影响。金属离子按 Mn+2＞Zn+2 = Ca+2＞Ba+2 的顺序将活性激活 1.5 - 2.5 倍。这些数据表明，一种胃蛋白酶抑制剂 A 可抑制的、与金属离子相关的天冬氨酸蛋白酶可能参与大鼠肺中 big 内皮素向内皮素的转化。
