HNMT
HNMT (histamine N-methyltransferase, also known as HMT) is a cytosolic enzyme that inactivates histamine by N-methylation. It has an important role in degrading histamine and in regulating the airway response to histamine. Browse Assay Genie's current range of HNMT research reagents below, or read on for the biology behind the target.
HNMT inactivates histamine by N-methylation. In mammals, histamine is metabolised by two major routes: N(tau)-methylation by histamine N-methyltransferase, and oxidative deamination by diamine oxidase. The HNMT gene encodes the first of these enzymes, which is found in the cytosol and uses S-adenosyl-L-methionine as the methyl donor. Through this activity the enzyme plays an important role in degrading histamine and in regulating the airway response to histamine.
The distinction between the two pathways matters in the nervous system. Diamine oxidase is not found in the central nervous system, so in the mammalian brain the neurotransmitter activity of histamine is controlled by N(tau)-methylation. HNMT therefore occupies a central position in terminating histamine signalling in the brain.
The HNMT protein belongs to the class I-like SAM-binding methyltransferase superfamily and the HNMT family, and HGNC places it among the small molecule methyltransferases. A common genetic polymorphism affects the activity of the gene product in red blood cells, and multiple alternatively spliced transcript variants encoding different proteins have been described for the HNMT gene. Mouse and rat each have an orthologous Hnmt gene, which allows the enzyme to be studied in common rodent models.
HNMT is one of the two major mammalian histamine-degrading pathways, making it a key enzyme for studying how histamine is cleared.
Because diamine oxidase is absent from the central nervous system, HNMT controls histamine neurotransmitter activity in the brain.
HNMT helps regulate the airway response to histamine, linking the enzyme to research on airway reactivity.
A common polymorphism alters HNMT activity in red blood cells, making the gene relevant to enzyme variation research.
HNMT inactivates histamine by N-methylation, using S-adenosyl-L-methionine as the methyl donor. It acts in the cytosol and plays an important role in degrading histamine and regulating the airway response to histamine. In the brain it is the main route controlling histamine activity.
HNMT is the approved symbol for histamine N-methyltransferase, and HMT is a listed alias. The enzyme carries the EC number 2.1.1.8. Multiple alternatively spliced transcript variants encoding different proteins have been reported for the gene.
Mouse and rat both have an orthologous Hnmt gene; check the datasheet of any product for its validated reactivity. In humans, a common genetic polymorphism affects HNMT activity levels in red blood cells.
Other histamine pathway enzymes, histamine receptors and small molecule methyltransferases with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P50135; product specifications from Assay Genie datasheets.