Thiols protect the inhibition of myocardial aconitase by peroxynitrite
Thiols protect the inhibition of myocardial aconitase by peroxynitrite
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DOI：
10.1006/abbi.1997.0496
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发表时间：
1998-02-01
影响因子：
3.9
通讯作者：
Schulz, R
中科院分区：
文献类型：
--
作者：
Cheung, PY;Danial, J;Schulz, R
过氧亚硝酸盐 (ONOO-) 是一种有效的心肌乌头酸酶抑制剂。由于 ONOO- 与巯基部分发生反应，我们研究了硫醇是否可以防止 ONOO- 介导的乌头酸酶抑制。在新鲜分离的大鼠心脏制备的心室匀浆中检查乌头酸酶活性。过氧亚硝酸盐，但不是一氧化氮供体 S-亚硝基-N-乙酰基-d,l-青霉胺 (0.03-300 mu M)，抑制乌头酸酶活性 (IC50 = 47 +/- 6 mu M)。 L-半胱氨酸 (0.03-300 μM)、谷胱甘肽 (0.03-3 mM) 和 N-(2-巯基丙酰基)-甘氨酸 (MPG, 0.03-3 mM) 可对抗 ONOO- (100 μM) 的抑制作用，效力顺序为 MPG > 谷胱甘肽 > L-半胱氨酸。 D-半胱氨酸 (3 mM) 对 L-半胱氨酸有保护作用，但 L-胱氨酸（L-半胱氨酸的氧化形式）没有提供保护作用。硫酸亚铁铵 (1 mM) 显着增强了 L-半胱氨酸提供的保护，但不增强谷胱甘肽对 MPG 的保护。硫醇以巯基依赖性且非立体特异性的方式保护心肌乌头酸酶免受 ONOO- 的抑制。这种保护与铁硫立方烷簇和酶活性位点半胱氨酸残基的氧化还原状态的维持有关。天然存在的硫醇和硫醇基药物都可能有助于在 ONOO- 产生过量的缺血再灌注损伤期间保护心脏。 (C) 1998 年学术出版社。
Peroxynitrite (ONOO-) is a potent inhibitor of myocardial aconitase. Because ONOO- reacts with sulfhydryl moieties, we investigated whether thiols protect against ONOO--mediated inhibition of aconitase. Aconitase activity was examined in ventricular homogenates prepared from freshly isolated rat hearts. Peroxynitrite, but not the nitric oxide donor S-nitroso-N-acetyl-d,l-penicillamine (0.03-300 mu M), inhibited aconitase activity (IC50 = 47 +/- 6 mu M). L-Cysteine (0.03-300 mu M), glutathione (0.03-3 mM), and N-(2-mercaptoproprionyl)-glycine (MPG, 0.03-3 mM) protected against the inhibitory effect of ONOO- (100 mu M) with the rank order of potency of MPG > glutathione > L-cysteine. D-Cysteine (3 mM) had a protective effect to L-cysteine, but L-cystine, the oxidized form of L-cysteine, offered no protection. Ferrous ammonium sulfate (1 mM) markedly enhanced the protection provided by L-cysteine, but not be glutathione of MPG. Thiols protect myocardial aconitase against inhibition by ONOO- in a manner which is sulfhydryl group dependent and not stereospecific. The protection is related to the maintenance of the redox state of the iron-sulfur cubane cluster and cysteine residues at the active site of the enzyme. Both naturally occurring thiols and thiol-based drugs may be useful to protect the heart during ischemia-reperfusion injury where there is an excessive production of ONOO-. (C) 1998 Academic Press.