Transketolase (TKT)
The protein contains 623 amino acids for an estimated molecular weight of 67878 Da.
Catalyzes the transfer of a two-carbon ketol group from a ketose donor to an aldose acceptor, via a covalent intermediate with the cofactor thiamine pyrophosphate. (updated: April 1, 2015)
Protein identification was indicated in the following studies:
- Goodman and co-workers. (2013) The proteomics and interactomics of human erythrocytes. Exp Biol Med (Maywood) 238(5), 509-518.
- Lange and co-workers. (2014) Annotating N termini for the human proteome project: N termini and Nα-acetylation status differentiate stable cleaved protein species from degradation remnants in the human erythrocyte proteome. J Proteome Res. 13(4), 2028-2044.
- Hegedűs and co-workers. (2015) Inconsistencies in the red blood cell membrane proteome analysis: generation of a database for research and diagnostic applications. Database (Oxford) 1-8.
- Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
- D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
Methods
The following articles were analysed to gather the proteome content of erythrocytes.
The gene or protein list provided in the studies were processed using the ID mapping API of Uniprot in September 2018. The number of proteins identified and mapped without ambiguity in these studies is indicated below.
Only Swiss-Prot entries (reviewed) were considered for protein evidence assignation.
| Publication | Identification 1 | Uniprot mapping 2 | Not mapped / Obsolete | TrEMBL | Swiss-Prot |
|---|---|---|---|---|---|
| Goodman (2013) | 2289 (gene list) | 2278 | 53 | 20599 | 2269 |
| Lange (2014) | 1234 | 1234 | 7 | 28 | 1224 |
| Hegedus (2015) | 2638 | 2622 | 0 | 235 | 2387 |
| Wilson (2016) | 1658 | 1528 | 170 | 291 | 1068 |
| d'Alessandro (2017) | 1826 | 1817 | 2 | 0 | 1815 |
| Bryk (2017) | 2090 | 2060 | 10 | 108 | 1942 |
| Chu (2018) | 1853 | 1804 | 55 | 362 | 1387 |
1 as available in the article and/or in supplementary material
2 uniprot mapping returns all protein isoforms as one entry
The compilation of older studies can be retrieved from the Red Blood Cell Collection database.
The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.
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| Variant | Description |
|---|---|
| dbSNP:rs17052920 | |
| SDDHD |
Biological Process
Carbohydrate metabolic process
Energy reserve metabolic process
Glyceraldehyde-3-phosphate biosynthetic process
Pathogenesis
Pentose-phosphate shunt
Pentose-phosphate shunt, non-oxidative branch
Regulation of growth
Ribose phosphate biosynthetic process
Small molecule metabolic process
Xylulose biosynthetic process
The reference OMIM entry for this protein is 606781
Transketolase; tkt
Tkt1
BIOCHEMICAL FEATURES
Transketolase (EC 2.2.1.1) is a thiamine-dependent enzyme that links the pentose phosphate pathway with the glycolytic pathway. The pentose phosphate pathway, which is active in most tissues, provides sugar phosphates for intermediary biosynthesis, especially nucleotide metabolism, and generates the biosynthetic reducing power for the cell in the form of NADPH. Transketolase is directly involved in the branch of the pathway that channels excess sugar phosphates to glycolysis, enabling the production of NADPH to be maintained under different metabolic conditions. NADPH is critical for maintaining cerebral glutathione, and thus it is likely that transketolase plays an important role in brain metabolism.CLONING
Abedinia et al. (1992) cloned a cDNA encoding transketolase from a human brain cDNA library. The library was screened with oligonucleotide probes based on the amino acid sequence of proteolytic fragments of the purified protein. Northern blot analysis showed that the transketolase mRNA is approximately 2.2 kb.GENE STRUCTURE
McCool et al. (1993) isolated transketolase cDNA clones and concluded that the gene is present in single copy in the haploid genome.MAPPING
Using a 10-kb genomic clone in fluorescence in situ hybridization, Lapsys et al. (1992) mapped the TKT gene to chromosome 3p14 at a site distal to the fragile site designated FRA3B (601153). TKT is therefore located at 3p14.3. Southern blot analysis of a series of rodent/human hybrid cell lines corroborated the localization. Coy et al. (1996) identified a transketolase-related gene (TKTL1; 300044) located in Xq28.ANIMAL MODEL
Xu et al. (2002) found that Tkt-null mouse embryos died at or before the morula stage. Disruption of 1 Tkt allele caused overall growth retardation and a specific reduction in adipose tissue. No phenotype was observed in Tkt +/- cornea, where Tkt expression was especially abundant in wildtype mice. The small female Tkt +/- mice mated infrequently and had few progeny when pregnant. ... More on the omim web site
Feb. 2, 2018: Protein entry updated
Automatic update: Uniprot description updated
Dec. 19, 2017: Protein entry updated
Automatic update: Uniprot description updated
March 16, 2016: Protein entry updated
Automatic update: OMIM entry 606781 was added.
Jan. 28, 2016: Protein entry updated
Automatic update: model status changed
Jan. 25, 2016: Protein entry updated
Automatic update: model status changed