Extracellular Enzyme Activity Measurements Using Fluorescent Substrate Derivatives

Enzymes play an important role in biochemical processes by being responsible for hydrolysis of various biomolecules such as proteins, carbohydrates, and organic phosphorus compounds. Microbial extracellular enzyme activities can be measured using fluorescent model substrates as proxies for natural substrates. Here 4-methylumbelliferyl phosphate, 4-methylumbelliferyl β-D-glucopyranoside, and L-leucine-7-amido-4-methylcoumarin hydrochloride are utilized to measure potential hydrolytic activities of phosphatase, glucosidase, and aminopeptidase, respectively, in natural seawater samples.