Inhibition of thiamin diphosphate dependent enzymes by 3-deazathiamin diphosphate

Organic & Biomolecular Chemistry Pub Date: 2004-05-25 DOI: 10.1039/B403619K

Abstract

3-Deazathiamin diphosphate (deazaTPP) and a second thiamin diphosphate (TPP) analogue having a benzene ring in place of the thiazolium ring have been synthesised. These compounds are both extremely potent inhibitors of pyruvate decarboxylase from Zymomonas mobilis; binding is competitive with TPP and is essentially irreversible even though no covalent linkage is formed. DeazaTPP binds approximately seven-fold faster than TPP and at least 25,000-fold more tightly (Ki less than 14 pM). DeazaTPP is also a potent inhibitor of the E1 subunit of α-ketoglutarate dehydrogenase from E. coli and binds more than 70-fold faster than TPP. In this case slow reversal of the inhibition could be observed and a Ki value of about 5 nM was calculated (ca. 500-fold tighter binding than TPP).

Graphical abstract: Inhibition of thiamin diphosphate dependent enzymes by 3-deazathiamin diphosphate
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