S-METHYL N,N-DIETHYLTHIOCARBAMATE SULFONE, A POTENTIAL METABOLITE OF DISULFIRAM AND POTENT INHIBITOR OF LOW K-M MITOCHONDRIAL ALDEHYDE DEHYDROGENASE
S-METHYL N,N-DIETHYLTHIOCARBAMATE SULFONE, A POTENTIAL METABOLITE OF DISULFIRAM AND POTENT INHIBITOR OF LOW K-M MITOCHONDRIAL ALDEHYDE DEHYDROGENASE
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DOI：
10.1016/0006-2952(94)00504-f
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发表时间：
1995-03-01
影响因子：
5.8
通讯作者：
LIPSKY, JJ
中科院分区：
文献类型：
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作者：
MAYS, DC;NELSON, AN;LIPSKY, JJ
双硫仑抑制肝醛脱氢酶（ALDH），导致乙醇摄入后乙醛蓄积。据认为双硫仑在体内的寿命太短而不能直接抑制ALDH，而是被生物转化为抑制该酶的活性代谢物。已在给予双硫仑的动物血液中鉴定出S-甲基N，N-二乙基硫代氨基甲酸酯（MeDTC）亚砜，其是ALDH的有效抑制剂（哈特和Faiman，Biochem Pharmacol 46：2285-2290，1993）。MeDTC砜是MeDTC亚砜的合理代谢产物。因此，我们研究了MeDTC砜对大鼠肝低K-m线粒体ALDH活性的影响，该酶是乙醛代谢的主要酶。MeDTC砜在体外抑制低钾线粒体ALDH，IC 50为0.42 +/- 0.04 μ M（平均值+/- SD，N = 5），与之相比，在相同条件下，双硫灵的IC 50为7.5 +/- 1.2 μ M。MeDTC砜对ALDH的抑制具有时间依赖性。ALDH活性的下降遵循伪一级动力学，在0.6 μ M MeDTC砜下表观半衰期为2.1分钟。MeDTC砜对ALDH的抑制作用显然是可逆的;稀释被抑制的酶不能恢复失去的活性。底物（乙醛，80 μ M）和辅因子（NAD，0.5 mM）一起完全保护ALDH免受MeDTC砜的抑制;单独的底物部分保护酶。在与酶一起孵育之前，向MeDTC砜中添加含巯基化合物谷胱甘肽（GSH）或二硫苏糖醇（DTT）可使MeDTC砜的IC 50增加7至14倍。GSH和DTT都不能恢复酶暴露于MeDTC砜后丢失的ALDH活性。这些研究的结果表明，MeDTC砜，一种潜在的代谢产物，是一种有效的，不可逆的低K-m线粒体ALDH抑制剂。
Disulfiram inhibits hepatic aldehyde dehydrogenase (ALDH) causing an accumulation of acetaldehyde after ethanol ingestion. it is thought that disulfiram is too short-lived in vivo to directly inhibit ALDH, but instead is biotransformed to reactive metabolites that inhibit the enzyme. S-Methyl N,N-diethylthiocarbamate (MeDTC) sulfoxide has been identified in the blood of animals given disulfiram and is a potent inhibitor of ALDH (Hart and Faiman, Biochem Pharmacol 46: 2285-2290, 1993). MeDTC sulfone is a logical metabolite of MeDTC sulfoxide. Therefore, we investigated the effects of MeDTC sulfone on the activity of rat hepatic low K-m mitochondrial ALDH, the major enzyme in the metabolism of acetaldehyde. MeDTC sulfone inhibited the low K,mitochondrial ALDH in vitro with an IC50 of 0.42 +/- 0.04 mu M (mean +/- SD, N = 5) compared with disulfram, which had an IC50 of 7.5 +/- 1.2 mu M under the same conditions, The inhibition of ALDH by MeDTC sulfone was time dependent. The decline in ALDH activity followed pseudo first-order kinetics with an apparent half-life of 2.1 min at 0.6 mu M MeDTC sulfone. Inhibition of ALDH by MeDTC sulfone was apparently irrversible; dilution of the inhibited enzyme did not restore lost activity. The substrate (acetaldehyde, 80 mu M) and cofactor (NAD, 0.5 mM) together completely protected ALDH from inhibition by MeDTC sulfone; substrate alone partially protected the enzyme. Addition of either thiol-containing compound glutathione (GSH) or dithiothreitol (DTT) to MeDTC sulfone before incubation with the enzyme increased the IC50 of MeDTC sulfone by 7- to 14-fold. Neither GSH nor DTT could restore lost ALDH activity after exposure of the enzyme to MeDTC sulfone. Results of these studies indicate that MeDTC sulfone, a potential metabolite of disulfram, is a potent, irreversible inhibitor of low K-m mitochondrial ALDH.