Histamine dehydrogenase is a homodimeric enzyme and catalyzes oxidative deamination of histamine. The gene encoding this enzyme has been sequenced and cloned by polymerase chain reactions and overexpressed in Escherichia coli.http://www.creative-enzymes.com/product/Histamine-Dehydrogenase-From-E-Coli-Recombinant_3444.html