NNMT is a monomeric, cytosolic enzyme (Mr ~ 30,000) that appears to be a number
of a family of methyltransferases that includes PNMT and TEMT (the thioether Smethyltransferase
present in mouse lung). NNMT catalyzes the N-methylation of
Nicotinamide and structurally related pyridine compounds (including pyridine itself) to form
positively charged pyridinium ions. Nicotinic acid (niacin), a commonly used lipid-lowering