Family

Cys/Met metabolism, pyridoxal phosphate-dependent enzyme (IPR000277)

Short name: Cys/Met-Metab_PyrdxlP-dep_enz

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 [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].

A number of pyridoxal-dependent enzymes involved in the metabolism of cysteine, homocysteine and methionine have been shown [PMID: 1577698, PMID: 8511966] to be evolutionary related. These enzymes are proteins of about 400 amino-acid residues. The pyridoxal-P group is attached to a lysine residue located in the central section of these enzymes.

One of these enzymes is the sulfhydrylase FUB7 from fungi such as Gibberella and Fusarium. The gene is part of a cluster that mediates the biosynthesis of fusaric acid, a mycotoxin with low to moderate toxicity to animals and humans, but with high phytotoxic properties [PMID: 26662839].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0030170 pyridoxal phosphate binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
CDD
Pfam
PROSITE patterns
PIRSF
PANTHER