Partial purification and characterization of peroxidase from pearl millet [Pennisetum glaucum (L.) R. Br.]
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Date
2010
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Publisher
CCSHAU
Abstract
This is the first report describing purification and characterization of peroxidase from pearl
millet grains. Peroxidase from pearl millet hybrid HHB 94 was purified using ammonium sulphate
fractionation, gel filtration chromatography and ion exchange chromatography using Sephadex G - 100
and DEAE cellulose respectively, to near homogeneity. The protocol yielded 41 % of peroxidase with
33.2 fold purification. The purified enzyme preparation has molecular weight of 31 kDa as determined
by gel filtration through Sephadex G – 100 and 30.4 kDa by SDS – PAGE suggesting that the enzyme
is a monomer. The enzyme exhibited maximum activity at pH 5.6 and 30 °C. It was most stable in the
pH range of 6.0 – 6.8 and at temperature below 35 °C. Peroxidase showed Km value of 0.10 mM and 11
mM for o – dianisidine and H2O2, respectively. Activity of peroxidase was highly inhibited by DTT, β –
mercaptoethanol , hydrazine and moderately inhibited by sodium azide, sodium borohydride, oxalic
acid, EDTA and DTNB. The enzyme activity was enhanced by Ca2+ and Fe3+ but moderately inhibited
by Mn2+ , Na+ and K+. Electrophoretic studies of pearl millet grain peroxidase revealed three isozymes
in HHB 94 and ICMA 94222 x 78/711. Banding pattern was similar in both but banding intensity
represented that ICMA 94222 x 78/711 had lesser peroxidase activity compared to HHB 94.
Description
Keywords
Enzymes, Millets, Purification, Inorganic acid salts, Grain, Proteins, Chromatography, Planting, Electrophoresis, Fractionation