4-Methylumbelliferyl-α-D-Glucopyranoside (4-Methylumbelliferyl-α-D-Glucose) is a fluorescent substrate for α-glucosidase, which releases the fluorescent moiety 4-methylumbelliferyl (4-MU) upon cleavage. 4-MU has pH-dependent fluorescence excitation activity, with excitation wavelengths of 320 nm at low pH (1.97-6.72) and 360 nm at high pH (7.12-10.3), respectively. The emission wavelength of 4-Methylumbelliferyl-α-D-Glucopyranoside increases with decreasing pH, ranging from 445-455 nm. 4-Methylumbelliferyl-α-D-Glucopyranoside can be used as a biomarker for Fabry and Pompe diseases to quantify α-glucosidase activity in infant blood spot samples.

Heptanoic acid is an organic compound composed of a seven-carbon chain terminating in a carboxylic acid. It is an oily liquid with an unpleasant rancid odor. It contributes to the odor of some rancid oils. It is slightly soluble in water but well soluble in ethanol and ether.

Casein Kinase Substrates 3 is a substrate of casein kinase.