Preparation of the substrate solution required mixing 0.05 M
guaiacol, 0.2 M H2O2, 0.2 M sodium phosphate buffer (pH 6.5)
and distiller water in a ratio of 1:1:1:7 v/v/v/v. Three mL of this
substrate solution were added to 25 mL of enzyme extract. The
reaction was monitored for 3 min at 420 nm in triplicate.
Equipment used for the assay was a multicell spectrophotometer
(UVeVIS spectrophotometer, model Genesis 2PC,
Spectronic, Japan) and a 1-cm path length quartz cuvette. The
enzyme activity was obtained by the slope of the resulting
absorbance (420 nm) v s time (DA min1
) and expressed in
units of peroxidase per ml of sample (U ml1
).