| Type: | Family | Name: | Cys/Met metabolism, pyridoxal phosphate-dependent enzyme |
| 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 [, , ]. 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 []. Inadequate levels of pyridoxal phosphate in the brain can cause neurological dysfunction, particularly epilepsy [].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 [].A number of pyridoxal-dependent enzymes involved in the metabolism of cysteine, homocysteine and methionine have been shown [, ] 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. | Short Name: | Cys/Met-Metab_PyrdxlP-dep_enz |
| DB identifier | Type | Name |
|---|---|---|
| IPR009651 | Family | Putative methionine gamma-lyase |
| IPR006238 | Family | Cystathionine beta-lyase, eukaryotic |
| IPR006235 | Family | O-acetylhomoserine/O-acetylserine sulfhydrylase |
| IPR011821 | Family | O-succinylhomoserine (thiol)-lyase |
| IPR006233 | Family | Cystathionine beta-lyase, bacterial |
| IPR006234 | Family | O-succinylhomoserine sulfhydrylase |
| IPR006237 | Family | Methionine gamma-lyase |
