Biochemical and Histopathological Effects of Aflatoxin on ...

<strong>and</strong> catalysis. GSH participates in reactions that destroy H20 2, orgamc
peroxides, free radicals <strong>and</strong> certain foreign compounds (Rana, 2002)
4.8 Repair <strong>and</strong> De-Novo Enzymes, Third Line Defense
Third line antioxidants are complex group <strong>of</strong> enzymes for repair <strong>of</strong>
damaged DNA, damaged protein, oxidized lipids <strong>and</strong> peroxide <strong>and</strong> also to
stop chain propagation <strong>of</strong> peroxyl lipid radical e.g. lipase, proteases, DNA
repair enzymes, transferase, methionine sulphoxide reductase etc. (Henle <strong>and</strong>
Linn, 1997)
4.9 Materials <strong>and</strong> Methods
4.9.1 Activity <strong>of</strong>Free Radical Scavenging Enzyme
4.9.1.a Estimation <strong>of</strong>Catalase (Maehly <strong>and</strong> Chance,1955)
Reagents
1. Phosphatebuffer
2. H202
: 0.01 M pH 7.0
:3OmM
The enzyme extracts were prepared by homogenizing the tissues in
O.DIM phosphate buffer, pH 7.0 <strong>and</strong> centrifuging at 5000 rpm. The reaction
mixture contained O.OIM phosphate buffer, 30mM hydrogen peroxide <strong>and</strong>
the enzyme extract. The estimation was done spectrophotometrically by
following the decrease in absorbance at 230nm. Specific activity was
expressed in terms <strong>of</strong> international units/mg protein. IIU = change in
absorbance/miniextinction coefficient (0.021)
37