Pyridoxal kinase (PDXK)
The protein contains 312 amino acids for an estimated molecular weight of 35102 Da.
Catalyzes the phosphorylation of the dietary vitamin B6 vitamers pyridoxal (PL), pyridoxine (PN) and pyridoxamine (PM) to form pyridoxal 5'-phosphate (PLP), pyridoxine 5'-phosphate (PNP) and pyridoxamine 5'-phosphate (PMP), respectively (PubMed:9099727, PubMed:10987144, PubMed:17766369, PubMed:19351586, PubMed:31187503) (Probable). PLP is the active form of vitamin B6, and acts as a cofactor for over 140 different enzymatic reactions. (updated: June 17, 2020)
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.
- 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.
- D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
- Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
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.
Biological Process
Cell population proliferation
Neutrophil degranulation
Pyridoxal 5'-phosphate salvage
Pyridoxal phosphate biosynthetic process
Small molecule metabolic process
Vitamin B6 metabolic process
Vitamin metabolic process
Water-soluble vitamin metabolic process
The reference OMIM entry for this protein is 179020
Pyridoxal kinase; pdxk
Pyridoxine kinase; pnk
Pkh
Vitamin b6 kinase
DESCRIPTION
Pyridoxal kinase (PDXK; EC 2.7.1.35) converts vitamin B6 to pyridoxal-5-phosphate (PLP), an essential cofactor in the intermediate metabolism of amino acids and neurotransmitters.CLONING
Hanna et al. (1997) cloned the cDNA encoding PDXK, which they referred to as PKH. The PDXK gene encodes a 312-amino acid polypeptide, and expression of the cDNA revealed pyridoxal kinase activity. Northern blot analysis revealed that a major 1.5-kb PDXK transcript was expressed in all tissues tested.GENE FUNCTION
The expression of PDXK shows circadian oscillations. Gachon et al. (2004) found that the expression of Pdxk in mouse liver and brain is regulated by the 3 PAR bZIP transcription factors, Dbp (124097), Hlf (142385), and Tef (179020), which also show circadian oscillations in expression. Mice devoid of all 3 transcription factors showed decreased levels of brain PLP, serotonin, and dopamine, and were highly susceptible to generalized spontaneous and audiogenic epilepsies that were frequently lethal.MAPPING
Hanna et al. (1997) reported that a BAC clone from the human 21q22.3 region contains almost the entire PDXK gene on 10 distinct exons.MOLECULAR GENETICS
Chern and Beutler (1976) concluded that alleles at a locus symbolized PNK determine the level of activity of pyridoxine kinase in erythrocytes: PNK(H) and PNK(L), for 'high' and 'low', respectively. The frequency of these 2 alleles was estimated to be 0.81 and 0.19 for whites and 0.35 and 0.65 for blacks. They suggested that the PNK(L) state of red cells is the result of a stability mutation. Data on gene frequencies of allelic variants were tabulated by Roychoudhury and Nei (1988). ... More on the omim web site
June 29, 2020: Protein entry updated
Automatic update: Entry updated from uniprot information.
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 179020 was added.
Jan. 28, 2016: Protein entry updated
Automatic update: model status changed
Jan. 25, 2016: Protein entry updated
Automatic update: model status changed