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Gene Review

Tkt  -  transketolase

Rattus norvegicus

Synonyms: TK, Transketolase
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Disease relevance of Tkt

  • In retinas of diabetic animals, benfotiamine treatment inhibited these three pathways and NF-kappaB activation by activating transketolase, and also prevented experimental diabetic retinopathy [1].
  • Replication-defective, amphotrophic retroviruses were constructed containing a chimeric varicella-zoster virus thymidine kinase (VZV TK) gene that is transcriptionally regulated by either the hepatoma-associated alpha-fetoprotein or liver-associated albumin transcriptional regulatory sequences [2].
  • 2. For the transketolase substrates, ribose 5-phosphate and xylulose 5-phosphate, the apparent Km values were 0.3 and 0.5 mM, respectively, in both liver and hepatoma [3].
  • The deficiency developed after 3 to 4 weeks and was evidenced by anorexia, weight-loss, and a significant increase in the erythrocyte transketolase activity ratio [4].
  • A rat brain tumor model was used to test the herpes simplex virus (HSV)-thymidine kinase (TK) gene for its ability to selectively kill C6 and 9L tumor cells in the brain following systemic administration of the nucleoside analog ganciclovir [5].

Psychiatry related information on Tkt


High impact information on Tkt

  • We have discovered that the lipid-soluble thiamine derivative benfotiamine can inhibit these three pathways, as well as hyperglycemia-associated NF-kappaB activation, by activating the pentose phosphate pathway enzyme transketolase, which converts glyceraldehyde-3-phosphate and fructose-6-phosphate into pentose-5-phosphates and other sugars [1].
  • VZV TK metabolically activated the nontoxic prodrug 6-methoxypurine arabinonucleoside (araM), ultimately leading to the formation of the cytotoxic anabolite adenine arabinonucleoside triphosphate (araATP) [2].
  • From the distribution of label at glucose carbons not labeled via the major pathway and from the carbon spin-spin splitting patterns observed, we conclude that transketolase is reversible whereas transaldolase is essentially irreversible in the nonoxidative pentose branch [8].
  • The kinetic properties of transaldolase and transketolase were similar in normal liver and in rapidly growing hepatoma 3924A [3].
  • Transketolase activity was highest in kidney (155%) and lowest in heart (26%) and skeletal muscle (23%) [3].

Chemical compound and disease context of Tkt


Biological context of Tkt


Anatomical context of Tkt


Associations of Tkt with chemical compounds


Other interactions of Tkt


Analytical, diagnostic and therapeutic context of Tkt

  • Northern blots showed that the transketolase mRNA is approximately 2.2 kb, close to the minimum expected, of which approximately 60% was represented in the largest cDNA clone [6].
  • Sequence analysis of the transketolase coding sequences reveals a number of homologies with related enzymes from other species [6].
  • With a few exceptions, immunocytochemistry indicated an overall decline of TK immunoreactivity and the decrease was not specific to vulnerable areas [22].
  • In contrast to the pronounced, general decline of TK protein, in situ hybridization revealed a regional decrease of 0-25% of TK mRNA in thiamine deficiency [22].
  • 1. Multiple forms of the enzyme, with distinct pI values in the range 7-8, have been detected in purified preparations by means of analytical isoelectric focusing and staining for TK [23].


  1. Benfotiamine blocks three major pathways of hyperglycemic damage and prevents experimental diabetic retinopathy. Hammes, H.P., Du, X., Edelstein, D., Taguchi, T., Matsumura, T., Ju, Q., Lin, J., Bierhaus, A., Nawroth, P., Hannak, D., Neumaier, M., Bergfeld, R., Giardino, I., Brownlee, M. Nat. Med. (2003) [Pubmed]
  2. Retroviral-mediated gene therapy for the treatment of hepatocellular carcinoma: an innovative approach for cancer therapy. Huber, B.E., Richards, C.A., Krenitsky, T.A. Proc. Natl. Acad. Sci. U.S.A. (1991) [Pubmed]
  3. Behavior of transaldolase (EC and transketolase (EC Activities in normal, neoplastic, differentiating, and regenerating liver. Heinrich, P.C., Morris, H.P., Weber, G. Cancer Res. (1976) [Pubmed]
  4. Increased axonal transport in peripheral nerves of thiamine-deficient rats. McLane, J.A., Khan, T., Held, I.R. Exp. Neurol. (1987) [Pubmed]
  5. Thymidine kinase-mediated killing of rat brain tumors. Barba, D., Hardin, J., Ray, J., Gage, F.H. J. Neurosurg. (1993) [Pubmed]
  6. Nucleotide and predicted amino acid sequence of a cDNA clone encoding part of human transketolase. Abedinia, M., Layfield, R., Jones, S.M., Nixon, P.F., Mattick, J.S. Biochem. Biophys. Res. Commun. (1992) [Pubmed]
  7. Cysteine proteinases are responsible for characteristic transketolase alterations in Alzheimer fibroblasts. Paoletti, F., Mocali, A., Tombaccini, D. J. Cell. Physiol. (1997) [Pubmed]
  8. 13C NMR studies of gluconeogenesis in rat liver cells: utilization of labeled glycerol by cells from euthyroid and hyperthyroid rats. Cohen, S.M., Ogawa, S., Shulman, R.G. Proc. Natl. Acad. Sci. U.S.A. (1979) [Pubmed]
  9. Combined suicide and cytokine gene therapy for peritoneal carcinomatosis. Lechanteur, C., Delvenne, P., Princen, F., Lopez, M., Fillet, G., Gielen, J., Merville, M.P., Bours, V. Gut (2000) [Pubmed]
  10. Effect of chronic alcohol administration on transketolase in the brain and the liver of rats. Jung, E.H., Itokawa, Y., Nishino, K. Am. J. Clin. Nutr. (1991) [Pubmed]
  11. In vivo retrovirus-mediated herpes simplex virus thymidine kinase gene therapy approach for adult T cell leukemia in a rat model. Murata, K., Fujita, M., Yamada, Y., Higami, Y., Shimokawa, I., Tsukasaki, K., Tanaka, Y., Maeda, M., Furukawa, K., Yoshiki, T., Shiku, H., Tomonaga, M. Jpn. J. Cancer Res. (1997) [Pubmed]
  12. Thiamin deficiency effects on rat leukocyte pyruvate decarboxylation rates. Hathcock, J.N. Am. J. Clin. Nutr. (1978) [Pubmed]
  13. Heterogeneous expression of transketolase in rat brain. Calingasan, N.Y., Sheu, K.F., Baker, H., Jung, E.H., Paoletti, F., Gibson, G.E. J. Neurochem. (1995) [Pubmed]
  14. Effect of ring substituents on the transketolase-catalyzed conversion of nitroso aromatics to hydroxamic acids. Corbett, M.D., Corbett, B.R. Biochem. Pharmacol. (1986) [Pubmed]
  15. Phenotypic conversion of TK-deficient cells following electroporation of functional TK enzyme. Dagher, S.F., Conrad, S.E., Werner, E.A., Patterson, R.J. Exp. Cell Res. (1992) [Pubmed]
  16. Prevention of incipient diabetic nephropathy by high-dose thiamine and benfotiamine. Babaei-Jadidi, R., Karachalias, N., Ahmed, N., Battah, S., Thornalley, P.J. Diabetes (2003) [Pubmed]
  17. Renal hypertrophy in experimental diabetes. Changes in pentose phosphate pathway activity. Steer, K.A., Sochor, M., McLean, P. Diabetes (1985) [Pubmed]
  18. High-dose thiamine therapy counters dyslipidaemia in streptozotocin-induced diabetic rats. Babaei-Jadidi, R., Karachalias, N., Kupich, C., Ahmed, N., Thornalley, P.J. Diabetologia (2004) [Pubmed]
  19. Effects of chronic alcohol feeding on thiamin status: biochemical and neurological correlates. Shaw, S., Gorkin, B.D., Lieber, C.S. Am. J. Clin. Nutr. (1981) [Pubmed]
  20. Effect of simultaneous thiamin and riboflavin deficiencies on the determination of transketolase and glutathione reductase. Vo-Khactu, K.P., Sims, R.L., Clayburgh, R.H., Sandstead, H.H. J. Lab. Clin. Med. (1976) [Pubmed]
  21. Postnatal development of thiamine metabolism in rat skeletal muscle. Matsuda, T., Tonomura, H., Baba, A., Iwata, H. Int. J. Biochem. (1991) [Pubmed]
  22. Regional reductions of transketolase in thiamine-deficient rat brain. Sheu, K.F., Calingasan, N.Y., Dienel, G.A., Baker, H., Jung, E.H., Kim, K.S., Paoletti, F., Gibson, G.E. J. Neurochem. (1996) [Pubmed]
  23. Immunoaffinity purification of rat liver transketolase: evidence for multiple forms of the enzyme. Paoletti, F., Aldinucci, D. Arch. Biochem. Biophys. (1986) [Pubmed]
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