2.6. PAL and PPO enzymes activity
PAL was extracted and assayed as described by Nguyen et al.
(2003). One gram of spathe was homogenized in 20 mL of 50 mM
borate buffer (pH 8.5) containing 5 mM 2-mercaptoethanol and
0.5 g PVPP. The homogenate was
filtered through three layers of
cotton cloth and then centrifuged at 18000
g for 20 min at 4 C.
PAL activity was determined in the supernatant, 0.3 mL of which
was added to a reaction mixture containing 0.7 mL of 100 mM L