Haugaard Niels, Levin Robert M
Division of Urology, School of Medicine, University of Pennsylvania, Philadelphia 19104-4283, USA.
Mol Cell Biochem. 2002 Jan;229(1-2):103-6. doi: 10.1023/a:1017924628110.
In a previous article we present results that demonstrated that the enzyme, choline acetyl transferase, was strongly activated by dihydrolipoic acid and that the oxidized form of this substance, lipoic acid itself, was an inhibitor of the enzyme and overcame the stimulatory effects of reduced lipoic acid. The experiments presented in this article show that dialysis of a partially purified preparation of choline acetyl transferase causes complete disappearance of enzyme activity and that addition of dihydrolipoic acid restores activity towards normal. In addition we present experiments with extracts of rat brain and heart as well as rabbit bladder tissue. In these extracts dihydrolipoic acid strongly activates the enzyme. Dialysis of brain and heart extracts causes loss of activity with partial restoration of activity by addition of dihydrolipoic acid. Reduced glutathione has no ability to stimulate activity of the enzyme. We conclude that the results of these experiments strongly support the view that dihydrolipoic acid acts as a coenzyme in the choline acetyl transferase reaction.
在之前的一篇文章中，我们展示的结果表明，胆碱乙酰转移酶这种酶被二氢硫辛酸强烈激活，且该物质的氧化形式，即硫辛酸本身，是该酶的抑制剂，并能克服还原型硫辛酸的刺激作用。本文所展示的实验表明，对部分纯化的胆碱乙酰转移酶制剂进行透析会导致酶活性完全消失，而添加二氢硫辛酸可使活性恢复正常。此外，我们还展示了用大鼠脑、心脏以及兔膀胱组织提取物进行的实验。在这些提取物中，二氢硫辛酸强烈激活该酶。对脑和心脏提取物进行透析会导致活性丧失，添加二氢硫辛酸可使活性部分恢复。还原型谷胱甘肽没有刺激该酶活性的能力。我们得出结论，这些实验结果有力地支持了二氢硫辛酸在胆碱乙酰转移酶反应中作为辅酶起作用这一观点。
