4-Methylumbelliferyl palmitate

4-Methylumbelliferyl palmitate, commonly names as 4-MUP, is a fluorescent probe that binds to lipases, enzymes responsible to assist on the hydrolysis of fats. In diagnosis, 4-MUP is used for screening of lysosomal storage diseases (LSD) caused by a deficiency of a single enzyme involved in the metabolism of glycoproteins, lipids or mucopolysaccharides.

Cholesterol ester storage disease and Wolman disease are recessive autosomal disorders caused by a deficiency in lysosomal acid lipase (LAL), also known as cholesteryl ester hydrolase. 4-Methylumbelliferyl palmitate (4-MUP) is a fluorogenic substrate for lysosomal acid lypase (LAL). 4-MUP is cleaved by LAL to release the fluorescent moiety 4-MU. 4-MU fluorescence is pH-dependent with excitation maxima of 320 and 360 nm at low (1.97-6.72) and high (7.12-10.3) pH, respectively, and an emission maximum ranging from 445 to 455 nM, increasing as pH decreases. 4-MUP may also be cleaved by other acid lipases. Recent advances allow the assessment of LAL activity in very small blood volumes using 4-MUP.

Cholesterol ester storage disease and Wolman disease are recessive autosomal disorders caused by a deficiency in lysosomal acid lipase (LAL), also known as cholesteryl ester hydrolase. 4-Methylumbelliferyl palmitate (4-MUP) is a fluorogenic substrate for LAL. It may also be cleaved by other acid lipases. Recent advances allow the assessment of LAL activity in very small blood volumes using 4-MUP.