. The supernatant (2 mL) was reacted with 5 mL of 500 mM Na2CO3 and 1
mL of five-fold diluted Folin-Ciocalteau reagent for 10 min. Absorbance was read against a blank at 660 nm.
One unit of enzyme activity was defined as the amount of enzyme that liberated 1μg of tyrosine per minute
under assay conditions