3-Nitrooxypropanol

3-Nitrooxypropanol, abbreviated 3NOP, is an organic compound with the formula HOCH2CH2CH2ONO2. It is the mononitrate ester of 1,3-propanediol. The compound is an inhibitor of the enzyme methyl coenzyme M reductase (MCR). MCR catalyzes the final step in methanogenesis. When it is fed to ruminants, their methane production is diminished.