Meta-Biol

• Pathways

Nicotinamide N-methyltransferase (NNMT) is a cytosolic protein which catalyses the N-methylation of nicotinamide (NAM aka vitamin B3) and other pyridines (Aksoy et al. 1994, 1995). It is mainly expressed in the liver and to a lesser extent in the kidney, lung, skeletal muscle, placenta and heart. NAM is a precursor for NAD+, an important cofactor in cellular redox states and energy metabolism. NNMT methylates NAM using S-adenosylmethionine (SAM) as the methyl donor to form 1-methylnicotinamide (MNA). Kraus et al. found Nnmt expression is increased in white adipose tissue and liver of obese and diabetic mice. An Nnmt knockdown stategy could protect against diet-induced obesity by increasing cellular energy expenditure thus could be a target for treating obesity and type 2 diabetes (Kraus et al. 2014). Experiments on rats with thrombolytic models suggest endogenous MNA could be a stimulator of the COX2/PGI2 pathway and thus regulate an anti-thrombotic effect (Chlopicki et al. 2007).