Feruloyl esterase (FAE, EC 3.1.1.73), also known as cinnamoyl esterase or cinnamic acid hydrolase, is an extracellular carboxylic acid esterase. It primarily degrades the ester bonds between arabinose, galactose, or hydroxycinnamic acid in cell wall polysaccharides or pectin.
Feruloyl esterase (FAE) catalyzes the decomposition of the substrate p-nitrophenyl ferulate to release p-nitrophenol (PNP), which has a maximum absorption peak at 405 nm. The enzyme activity is calculated by measuring the rate of increase in absorbance at this wavelength.