Pyridoxine kinase (IPR004625)

Short name: PyrdxlKinase

Overlapping homologous superfamilies

Family relationships


Pyridoxal phosphate is the active form of vitamin B6 (pyridoxine or pyridoxal). Pyridoxal 5'-phosphate (PLP) is a versatile catalyst, acting as a coenzyme in a multitude of reactions, including decarboxylation, deamination and transamination [PMID: 8690703, PMID: 7748903, PMID: 15189147]. PLP-dependent enzymes are primarily involved in the biosynthesis of amino acids and amino acid-derived metabolites, but they are also found in the biosynthetic pathways of amino sugars and in the synthesis or catabolism of neurotransmitters; pyridoxal phosphate can also inhibit DNA polymerases and several steroid receptors [PMID: 17109392]. Inadequate levels of pyridoxal phosphate in the brain can cause neurological dysfunction, particularly epilepsy [PMID: 16763894].

PLP enzymes exist in their resting state as a Schiff base, the aldehyde group of PLP forming a linkage with the epsilon-amino group of an active site lysine residue on the enzyme. The alpha-amino group of the substrate displaces the lysine epsilon-amino group, in the process forming a new aldimine with the substrate. This aldimine is the common central intermediate for all PLP-catalysed reactions, enzymatic and non-enzymatic [PMID: 15581583].

This entry represents pyridoxal kinase (EC:, which is required for the synthesis of pyridoxal-5-phosphate from vitamin B6, and catalyses the conversion of pyridoxal to pyridoxal 5'-phosphate in the presence of ATP. Escherichia coli has an enzyme PdxK that acts in vitro as a pyridoxine/pyridoxal/pyridoxamine kinase, but mutants lacking PdxK activity retain a specific pyridoxamine kinase, PdxY [PMID: 9537380]. PdxY acts in the salvage pathway of pyridoxal 5'-phosphate biosynthesis. Mammalian forms of pyridoxal kinase are more similar to PdxY than to PdxK.

GO terms

Biological Process

GO:0009443 pyridoxal 5'-phosphate salvage

Molecular Function

GO:0008478 pyridoxal kinase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
  • cd01173 (pyridoxal_pyridoxamine_kinase)