monoacyloglicerole

Monoacylglycerol, also known as monoacylglyceride (MAG), is a glycerol molecule bearing a single fatty acid esterified to one hydroxyl group, while the remaining two hydroxyls remain free. Depending on which position on the glycerol backbone is occupied by the fatty acid, MAG can be described as 1-MAG, 2-MAG, or 3-MAG (sn-1, sn-2, sn-3). In practice, the term often refers to the major forms produced during fat digestion, particularly 2-MAG.

Biological context and digestion

In mammals, dietary triacylglycerol is hydrolyzed by pancreatic lipase (with colipase) in the small intestine, yielding 2-monoacylglycerol and free fatty acids as the primary products absorbed by the intestinal mucosa. Within enterocytes, MAG can be re-esterified to diacylglycerol and then to triacylglycerol by monoacylglycerol acyltransferase (MGAT) and diacylglycerol acyltransferase (DGAT). These newly formed triacylglycerols are packaged into chylomicrons for transport via the lymphatic system. MAG can also be degraded or remodeled locally, but re-esterification and incorporation into TAG are central to fat absorption and energy storage.

Industrial and dietary use

Commercial monoacylglycerols are often produced by hydrolysis or glycerolysis of fats and oils and typically occur as mixtures with diacylglycerols. They are widely used as emulsifiers in the food industry, contributing to texture and stability. In food labeling, mixtures of mono- and diacylglycerols are commonly designated as E471. MAGs also occur in biological tissues as intermediates in lipid metabolism.

See also: glycerol, triglyceride, diglyceride, lipase, MGAT, DGAT.