Purity: > 95% by SDS - PAGE Format: Liquid. In 20mM Tris-HCl(pH8.0) buffer containing 10% glycerol . Histamine N-methyltransferase (HNMT) is found in the cytosol and uses S-adenosyl-L-methionine as the methyl donor. HNMT inactivates histamine by N-methylation. Histamine is involved in regulation and modulation of immune response through the stimulation of four distinct subtypes of receptors, H1, H2, H3, and H4, present on the target cells. Histamine is inactivated by the histamine-metabolizing enzyme histamine N-methyltransferase (HNMT) in bronchus, kidney, and the central nervous system. It plays an important role in degrading histamine and in regulating the airway response to histamine. Recombinant human HNMT protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography.