4methylumbelliferyl caprylate

4-Methylumbelliferyl caprylate (MUCAP) is a fluorogenic substrate for C8 esterase. MUCAP is cleaved by C8 esterase to release the fluorescent moiety 4-methylumbelliferyl (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.