histamiiniNmetyyltransferaasin

Histamiini N-metyylitransferaasi, often abbreviated as HNMT, is an enzyme that plays a crucial role in the metabolism of histamine. This enzyme belongs to the methyltransferase family and is responsible for catalyzing the transfer of a methyl group from S-adenosyl-L-methionine (SAM) to the imidazole ring of histamine. This process results in the formation of N-methylhistamine, which is a less biologically active metabolite.

The primary function of HNMT is to inactivate histamine, a biogenic amine involved in various physiological processes such as immune responses, neurotransmission, and gastric acid secretion. By methylating histamine, HNMT effectively reduces its concentration and consequently its effects. This enzymatic activity is vital for maintaining histamine homeostasis within the body.

HNMT is found in various tissues throughout the body, with particularly high activity observed in the liver, kidneys, and lungs. Its expression and activity can be influenced by genetic factors and environmental stimuli. Dysregulation of HNMT activity has been implicated in certain health conditions, although its precise role in various diseases is still an active area of research. Understanding the mechanisms and regulation of HNMT is important for comprehending histamine metabolism and its implications for human health.