转酮醇酶的底物抑制作用。

Substrate inhibition of transketolase.

作者信息

Solovjeva Olga N, Kovina Marina V, Kochetov German A

机构信息

Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia.

Department of Hepatopancreatobiliary and Regenerative Surgery, Sechenov First Moscow State Medical University, Ministry of Health of the Russian Federation, Trubetskaya Street 8/2, 119991 Moscow, Russia.

出版信息

Biochim Biophys Acta. 2016 Mar;1864(3):280-282. doi: 10.1016/j.bbapap.2015.12.005. Epub 2015 Dec 17.

DOI:10.1016/j.bbapap.2015.12.005

PMID:26708478

Abstract

We studied the influence of the acceptor substrate of transketolase on the activity of the enzyme in the presence of reductants. Ribose-5-phosphate in the presence of cyanoborohydride decreased the transketolase catalytic activity. The inhibition is caused by the loss of catalytic function of the coenzyme-thiamine diphosphate. Similar inhibitory effect was observed in the presence of NADPH. This could indicate its possible regulatory role not only towards transketolase, but also towards the pentose phosphate pathway of carbohydrate metabolism overall, taking into account the fact that it inhibits not only transketolase but also another enzyme of the pentose phosphate pathway--glucose 6-phosphate dehydrogenase [Eggleston L.V., Krebs H.A. Regulation of the pentose phosphate cycle, Biochem. J. 138 (1974) 425-435].

摘要

我们研究了转酮醇酶的受体底物在还原剂存在时对该酶活性的影响。在氰基硼氢化钠存在下，5-磷酸核糖降低了转酮醇酶的催化活性。这种抑制是由辅酶硫胺素二磷酸催化功能的丧失引起的。在存在NADPH的情况下也观察到了类似的抑制作用。考虑到它不仅抑制转酮醇酶，还抑制磷酸戊糖途径的另一种酶——葡萄糖6-磷酸脱氢酶[埃格尔斯顿L.V.，克雷布斯H.A. 磷酸戊糖循环的调节，《生物化学杂志》138 (1974) 425 - 435]，这可能表明它不仅对转酮醇酶，而且对整个碳水化合物代谢的磷酸戊糖途径都可能具有调节作用。