Histidine decarboxylase(HDC)

General Information about Histidine decarboxylase (HDC)

Histidine decarboxylase (HDC) is an enzyme responsible for catalyzing the decarboxylation of histidine to form histamine. In mammals, histamine is an important biogenic amine, which plays a regulatory role in neurotransmission, gastric acid secretion and immune response. Histidine decarboxylase is the only member of histamine synthesis pathway, producing histamine step by step. Histamine cannot be produced by any other known enzymes. Therefore, HDC is the main source of histamine in most mammals and eukaryotes. The enzyme uses pyridoaldehyde 5′-phosphate (PLP) as a cofactor, which is similar to many amino acid decarboxylases. Eukaryotes, as well as gram-negative bacteria share a common HDC, while gram-positive bacteria employ an evolutionarily unrelated pyruvoyl-dependent HDC. In humans, histidine decarboxylase is encoded by the HDC gene.