Mammalian histidine decarboxylase: from structure to function.

Histamine is a multifunctional biogenic amine with relevant roles in intercellular communication, inflammatory processes and highly prevalent pathologies. Histamine biosynthesis depends on a single decarboxylation step, carried out by a PLP-dependent histidine decarboxylase activity (EC 4.1.1.22), an enzyme that still remains to be fully characterized. Nevertheless, during the last few years, important advances have been made in this field, including the generation and validation of the first three-dimensional model of the enzyme, which allows us to revisit previous results and conclusions. This essay provides a comprehensive review of the current knowledge of the structural and functional characteristics of mammalian histidine decarboxylase.