Pyridoxal phosphate-dependent decarboxylase, major domain
IPR002129
Definition
A number of pyridoxal-dependent decarboxylases share regions of sequence similarity, particularly in the vicinity of a conserved lysine residue, which provides the attachment site for the pyridoxal-phosphate (PLP) group [[cite:PMID:8181483], [cite:PMID:2124279]]. Among these enzymes are aromatic-L-amino-acid decarboxylase (L-dopa decarboxylase or tryptophan decarboxylase), which catalyses the decarboxylation of tryptophan to tryptamine PMID:8889823; tyrosine decarboxylase, which converts tyrosine into tyramine; histidine decarboxylase, which catalyses the decarboxylation of histidine to histamine PMID:2300558; L-aspartate decarboxylase, which converts aspartate to beta-alanine PMID:24415726; and phenylacetaldehyde synthase that catalyses the decarboxylation of L-phenylalanine to 2-phenylethylamine PMID:16766535. These enzymes belong to the group II decarboxylases [[cite:PMID:8181483], [cite:PMID:8889823]]. 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 [[cite:PMID:8690703], [cite:PMID:7748903], [cite: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 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 PMID:15581583.
9 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
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