LOX activity was assayed using the methods of Sovrano et al.
(2006). The reaction mixture consisted of 10 L of linoleic acid
substrate, 4 mL of water, 1 mL of 0.1N NaOH and 5 L of Tween
20. The mixture was shaken vigorously and diluted to 20 mL with
water. The assay was performed at 25 ◦C by adding 50 L of crude
extract to 100 L of substrate and 1.85 mL of buffer (100 mM phosphate
buffer, pH 6.8). One unit of activity was determined in units of
0.1 per minute increase in absorbance at 234 nm. Catechol oxidase
activity was assayed according to Dan et al. (1999). The reaction
mixture contained 1.95 mL of 0.1 M phosphate buffer (pH 6.8),
1 mL of 10 mM caffeic acid substrate, and 0.05 mL of crude enzyme
extract. One unit of enzyme activity was defined as the amount of
the enzyme that produced an increase in absorbance at 420 nm of
0.001 per minute. The protein concentration in enzyme extracts
was determined by the standard Bradford method, using bovine
serum albumin as a standard protein.
CA