L-Histidine 7-amido-4-methylcoumarin is an enzyme substrate. Substrates of glycosidases, phosphatases and esterases are commonly employed in microbiology, food/water, environmental and ELISA testing. Assays of peptidases are more important in clinical enzyme assays and AMC is the fluorophore employed in most of these substrates. AMC is extremely versatile since the carboxy-terminus of any amino acid or peptide can be linked to it. Most enzymes are tolerant towards the AMC structure. Typically, kinetics of enzyme reactions remain undisturbed and few inhibitory effects are observed. Due to the low basicity of the amino group, AMC is not subject to acid base equilibrium at physiological pH. Therefore, assays using AMC substrates are rather tolerant of pH.
