Transketolase-like-1
| Transketolase-like protein 1 | ||
|---|---|---|
| Properties of human protein | ||
| Mass / length primary structure | 596 amino acids | |
| Secondary to quaternary structure | Homodimer | |
| Cofactor | Calcium, thiamine pyrophosphate | |
| Isoforms | > 3 | |
| Identifier | ||
| Gene names | TKTL1 ; TKT2 | |
| External IDs | ||
| Enzyme classification | ||
| EC, category | 2.2.1.1 , transferase | |
| Response type | Transfer of a ketol group | |
| Substrate | Xylulose-5-phosphate + D- ribose-5-phosphate | |
| Products | D- glyceraldehyde-3-phosphate + sedoheptulose-7-phosphate | |
| Occurrence | ||
| Homology family | Transketolase | |
| Parent taxon | Chordates | |
Transketolase-like-1 (TKTL1) is an enzyme related to transketolase and catalyzes the same reactions as it. While transketolases are formed in many living things, this enzyme was only developed in mammals. There are at least three isoforms of TKTL1 in humans, each localized in different tissue types, namely the heart, brain, lungs, kidneys, placenta, muscles and pancreas. The enzyme is also found in various neurodegenerative diseases , diabetes mellitus and some cancers . In the case of fast-growing, malignant tumor cells in particular, it is responsible for their biochemical properties to follow an anaerobic metabolic pathway even when there is sufficient oxygen supply ; the TKTL1 can thus explain the so-called glucose fermentation in tumor cells ( Warburg effect ).
The overexpression of TKTL1 protein in some tumor types is also discussed as a potential marker for the clinical course or a possible target in tumor therapy. At least the mRNA transcripts of TKTL1 could be inhibited experimentally in a cell culture of human hepatoma cells (HepG2) with iRNA. TKTL1 could also play a role as a tumor marker in the clinical course of some types of cancer, possibly also in throat cancer .
Individual evidence
- ↑ JF Coy, D. Dressler, J. Wilde, P. Schubert: Mutations in the transketolase-like gene TKTL1: clinical implications for neurodegenerative diseases, diabetes and cancer. In: Clin Lab. 51 (5-6), 2005, pp. 257-273. PMID 15991799 .
- ↑ UniProt P51854
- ↑ M. Foldi, E. Stickeler, L. Bau, O. Kretz, D. Watermann, G. Gitsch, G. Kayser, A. Zur Hausen, JF Coy: Transketolase protein TKTL1 overexpression: A potential biomarker and therapeutic target in breast cancer. In: Oncol Rep. 17 (4), 2007, pp. 841-845. PMID 17342325
- ↑ S. Zhang, JH Yang, CK Guo, PC Cai: Gene silencing of TKTL1 by RNAi inhibits cell proliferation in human hepatoma cells. In: Cancer Letters . 253 (1), 2007, pp. 108-114. PMID 17321041
- ↑ HU Volker, M. Scheich, B. Schmausser, U. Kammerer, M. Eck: Overexpression of transketolase TKTL1 is associated with shorter survival in laryngeal squamous cell carcinomas. In: Eur Arch Otorhinolaryngol. 2007. PMID 17639446
