Histamine and Methylation
Histamine Histamine is a hydrophilic vasoactive amine derived from histidine through carboxylation by L-histidine decarboxylase1. Histamine, once formed, can be stored or rapidly undergo deamination or demethylation, which is catalyzed by diamine oxidase (DAO) or histamine-N-methyltransferase (HNMT) respectively. IgE antibodies on immune cells cause them to degranulate, releasing specific alkaloids and amines capable of displacing