In several tumors the transketolase activity, controlled inter alia by enzymes of the pentose phosphate pathway which is an alternative, energy generating reaction-cascade to glycolysis, has been correlated with proliferation. The increase of thiamine-dependent transketolase enzyme reactions is induced especially through upregulated transketolase-like enzyme 1 (TKTL1)-activity; that shows TKTL1...

the calcium binding sites of bakers' yeast transketolase (tk) was elucidated by estimating the pka values of the functional groups that bind to calcium. these pka's were found to be 6.25 and 7.2 relating to the pka's of the two immidazol moieties of histidine residues on the enzyme. the rate of the binding of calcium to the enzyme was obtained separately as a function of ph. maxi...

Derivatives of phenyl-keto butenoic acids have been reported to be inhibitors of pyruvate decarboxylase, (PDC). The inhibition of transketolase, a thiamine requiring enzyme such as PDF, by meta nitrophenyl derivative of 2-oxo-3-butenoic acid (MNPB) is reported here. These studies indicate that the inhibitor binds to the enzyme at the active site. A two-step inhibition was observed, first th...

To investigate the effect of increased plastid transketolase on photosynthetic capacity and growth, tobacco (Nicotiana tabacum) plants with increased levels of transketolase protein were produced. This was achieved using a cassette composed of a full-length Arabidopsis thaliana transketolase cDNA under the control of the cauliflower mosaic virus 35S promoter. The results revealed a major and un...

We detected a strong upregulation of the mutated transketolase transcript (TKTL1) in human hepatoma cell line HepG2, whereas transketolase (TKT) and transketolase-like-2 (TKTL2) transcripts were not upregulated. We inhibited the expression of TKTL1 by RNAi in HepG2 cells. It was found that total transketolase activity was dramatically downregulated and the proliferation of cancer cells was sign...

Besides transketolase (TKT), a thiamin-dependent enzyme of the pentose phosphate pathway, the human genome encodes for two closely related transketolase-like proteins, which share a high sequence identity with TKT. Transketolase-like protein 1 (TKTL1) has been implicated in cancerogenesis as its cellular expression levels were reported to directly correlate with invasion efficiency of cancer ce...

The uses of 3-formylbenzoic acid and 4-formylbenzoic acid as molecular probes along with previous and new transketolase mutants revealed the factors governing the rate of reaction between transketolase and aromatic aldehydes. The novel α,α-dihydroxyketones were produced at 15 to 30-fold higher yields and up to 250-fold higher specific activities with D469T TK when compared to those obtained for...

Transketolase (TK, EC.2.2.1.1) is a thiamine-dependent enzyme which is widely used for assessing thiamine deficiency. The TK activity in erythrocytes is usually decreased during thiamine deficiency and this activity can be enhanced in vitro by the addition of thiamine pyrophosphate (TPP). The relative increase in enzyme activity, expressed as a percentage, is called the TPP effect. The TK kinet...