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QuickView for Pyridoxal phosphate-dependent transferase, major domain (biogroup)
- 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.The monomer of PLP-dependent transferases consists of two domains, a large domain and a small domain. This entry represents the large domain, which has a 3-layer alpha/beta/alpha sandwich topology. This domain can be found in the following PLP-dependent transferase families:Aspartate aminotransferase (AAT)-like enzymes, such as aromatic aminoacid aminotransferase AroAT, glutamine aminotransferase and kynureninase.Beta-eliminating lyases, such as tyrosine phenol lyase and tryptophanase.Pyridoxal-dependent decarboxylases, such as DOPA decarboxylase and glutamate decarboxylase beta (GadB).Cystathionine synthase-like enzymes, such as cystalysin, methionine gamma-lyase (MGL), and cysteine desulphurase (IscS).GABA-aminotransferase-like enzymes, such as ornithine aminotransferase and serine hydroxymethyltransferase.Ornithine decarboxylase major domain.
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