F
IPR004625

Pyridoxine kinase

InterPro entry
Short namePyrdxlKinase
Overlapping
homologous
superfamilies
 
Ribokinase-like (IPR029056)
family relationships

Description

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
[2, 7, 3]
. 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
[4]
. Inadequate levels of pyridoxal phosphate in the brain can cause neurological dysfunction, particularly epilepsy
[5]
.

PLP enzymes exist in their resting state as a Schiff base, the aldehyde group of PLP forming a linkage with the ε-amino group of an active site lysine residue on the enzyme. The α-amino group of the substrate displaces the lysine ε-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
[1]
.

This entry represents pyridoxal kinase (
2.7.1.35
), 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 actsin vitroas a pyridoxine/pyridoxal/pyridoxamine kinase, but mutants lacking PdxK activity retain a specific pyridoxamine kinase, PdxY
[6]
. PdxY acts in the salvage pathway of pyridoxal 5'-phosphate biosynthesis. Mammalian forms of pyridoxal kinase are more similar to PdxY than to PdxK.

References

1.Reaction specificity in pyridoxal phosphate enzymes. Toney MD. Arch. Biochem. Biophys. 433, 279-87, (2005). View articlePMID: 15581583

2.Pyridoxal enzymes: mechanistic diversity and uniformity. Hayashi H. J. Biochem. 118, 463-73, (1995). View articlePMID: 8690703

3.Pyridoxal phosphate enzymes: mechanistic, structural, and evolutionary considerations. Eliot AC, Kirsch JF. Annu. Rev. Biochem. 73, 383-415, (2004). View articlePMID: 15189147

4.Exploring the pyridoxal 5'-phosphate-dependent enzymes. Mozzarelli A, Bettati S. 6, 275-87, (2006). PMID: 17109392

5.B6-responsive disorders: a model of vitamin dependency. Clayton PT. J. Inherit. Metab. Dis. 29, 317-26, (2006). View articlePMID: 16763894

6.Identification and function of the pdxY gene, which encodes a novel pyridoxal kinase involved in the salvage pathway of pyridoxal 5'-phosphate biosynthesis in Escherichia coli K-12. Yang Y, Tsui HC, Man TK, Winkler ME. J. Bacteriol. 180, 1814-21, (1998). View articlePMID: 9537380

7.Pyridoxal phosphate-dependent enzymes. John RA. Biochim. Biophys. Acta 1248, 81-96, (1995). View articlePMID: 7748903

GO terms

cellular component

  • None

Cross References

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