The CAT activity was measured by recording
H2O2 disappearance characterized by an absorbance
decrease at 240 nm according to a method described by
Aebi (1984), with modifications. A 5 g sample was mixed
with 25 mL of 50 mM phosphate buffer (pH 7.0) at
13,500 rpm using a homogenizer (Ultra-Turrax T25 basic,
IkaWerke GmbH & Co., Staufen im Breisgau, Germany) for 15 s. The mixture was centrifuged at 1,000 x g at 2C for
15 min. The supernatant of the mixture was removed and
filtered with Whatman filter paper No. 1 (GE Healthcare
Life Sciences, Amersham, Buckinghamshire, UK). Then,
100 μL of the filtered supernatant was mixed with 2.9 mL of
30 mM H2O2. The decrease in absorbance at 240 nm was
recorded every 30 s for 3 min. The catalase activity was calculated
as follows: