Kaufman E E, Nelson T
Laboratory of Cerebral Metabolism, National Institute of Mental Health, United States Public Health Service, Department of Health and Human Services, Bethesda, Maryland 20892.
Neurochem Res. 1991 Sep;16(9):965-74. doi: 10.1007/BF00965839.
Two enzymes have been found which catalyze the initial step in the catabolism of GHB. The oxidation of GHB to SSA, catalyzed by both of these enzymes, is coupled to the reduction of an oxoacid. In the case of the mitochondrial transhydrogenase, the coupling is obligatory. Although coupling is not obligatory for the GHB dehydrogenase, the stimulation provided by the coupled reaction, and the nature of the kinetics of the uncoupled reaction, may not only allow the reaction to proceed, but may provide a means of regulating the rate of the reaction under in vivo conditions. Since the oxidation of GHB to SSA is the rate limiting step in the overall catabolic pathway (the rate of conversion of GHB to SSA proceeds at approximately one one thousandth of the rate at which SSA is oxidized to succinate by SSA dehydrogenase (30)), factors which regulate the rate of either or both of these enzymes will, in turn, influence tissue levels of endogenous GHB as well as the duration and magnitude of the physiological effect of a dose of GHB.
已发现两种酶可催化γ-羟基丁酸（GHB）分解代谢的初始步骤。这两种酶均催化GHB氧化为琥珀酸半醛（SSA），该过程与一种含氧酸的还原相偶联。在线粒体转氢酶的情况下，这种偶联是必然的。尽管对于GHB脱氢酶而言偶联并非必然，但偶联反应提供的刺激以及未偶联反应的动力学性质，不仅可能使反应得以进行，而且可能提供一种在体内条件下调节反应速率的方式。由于GHB氧化为SSA是整个分解代谢途径中的限速步骤（GHB转化为SSA的速率约为SSA脱氢酶将SSA氧化为琥珀酸速率的千分之一（30）），因此调节这两种酶中任何一种或两种酶的速率的因素，反过来会影响内源性GHB的组织水平以及一定剂量GHB的生理效应的持续时间和强度。
