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Updated: Mar 28, 2026

Direct Detection of the Acetate-forming Activity of the Enzyme Acetate Kinase
Published on: December 19, 2011
Substrate inhibition of transketolase
Olga N Solovjeva1, Marina V Kovina2, German A Kochetov1
1Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia.
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].
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