Laurent V, Stefano G, Salzet M
Centre de biologie cellulaire, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France.
Regul Pept. 1997 Mar 26;69(2):53-61. doi: 10.1016/s0167-0115(96)02121-0.
A soluble 65582.9 Da (in MALDI-TOF) angiotensin converting (ACE)-like enzyme has been purified by a captopril-Sepharose affinity column chromatography from the mollusk Mytilus edulis. This glycosylated peptidyl dipeptidase, with an N-terminal sequence of LDPELSPGCFVANQAGGQLF, hydrolyses the Phe8-His9 bond (at pH 8.4 and 37 degrees C) of angiotensin I with a high catalytic activity i.e. Km: 168 microM and Kcat/Km: 262 s-1 mM-1. The hydrolysis of angiotensin I is inhibited by the specific ACE inhibitors captopril and lisonopril (Ic50 = 50 nM). This activity is increased by Cl- (optimal Cl- concentration 400 mM) and by Zn2+. This zinc metallopeptidase also attacks peptides having a Gly-His, Gly-Phe or a Phe-His bond in their sequence e.g. leucine-enkephalin (Kcat/Km: 1200 s-1 mM-1 or bradykinin (Kcat/Km: 2500 s-1 mM-1). Mytilus ACE displays properties of the C-domain of human ACE, indicating a high degree of conservation during evolution. These results are consistent with an ACE activity implicated in metabolism of several neuropeptides in mollusks.
一种分子量为65582.9道尔顿（基质辅助激光解吸电离飞行时间质谱测定）的可溶性血管紧张素转换（ACE）样酶，已通过卡托普利-琼脂糖亲和柱色谱法从贻贝（紫贻贝）中纯化出来。这种糖基化的肽基二肽酶，其N端序列为LDPELSPGCFVANQAGGQLF，在pH 8.4和37℃条件下，以高催化活性水解血管紧张素I的Phe8-His9键，即Km为168微摩尔，Kcat/Km为262 s-1 mM-1。血管紧张素I的水解受到特异性ACE抑制剂卡托普利和赖诺普利的抑制（半数抑制浓度Ic50 = 50纳摩尔）。氯离子（最佳氯离子浓度400毫摩尔）和锌离子可增强这种活性。这种锌金属肽酶还能作用于序列中含有Gly-His、Gly-Phe或Phe-His键的肽，例如亮氨酸脑啡肽（Kcat/Km：1200 s-1 mM-1）或缓激肽（Kcat/Km：2500 s-1 mM-1）。贻贝ACE表现出人类ACE C结构域的特性，表明在进化过程中具有高度保守性。这些结果与ACE活性参与软体动物几种神经肽的代谢一致。
