Effect of calcium on immobilization of rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) peroxidase for bioassays in sodium alginate and Agarose gel |
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Authors: | Sareeta Nahakpam Puneeta Singh Kavita Shah |
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Institution: | (1) Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi, 221 005, India;(2) Department of Zoology (Biochemistry), MMV, Banaras Hindu University, Varanasi, 221 005, India |
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Abstract: | The direct immobilization of soluble peroxidase isolated and partially purified from shoots of rice seedlings in calcium alginate
beads and in calcium agarose gel was carried out. Peroxidase was assayed for guaiacol oxidation products in presence of hydrogen
peroxide. The maximum specific activity and immobilization yield of the calcium agarose immobilized peroxidase reached 2,200
U mg−1 protein (540 mU cm−3 gel) and 82%, respectively. In calcium alginate the maximum activity of peroxidase upon immobilization was 210 mU g−1 bead with 46% yield. The optimal pH for agarose immobilized peroxidase was 7.0 which differed from the pH 6.0 for soluble
peroxidase. The optimum temperature for the agarose immobilized peroxidase however was 30°C, which was similar to that of
soluble peroxidase. The thermal stability of calcium agarose immobilized peroxidase significantly enhanced over a temperature
range of 30∼60°C upon immobilization. The operational stability of peroxidase was examined with repeated hydrogen peroxide
oxidation at varying time intervals. Based on 50% conversion of hydrogen peroxide and four times reuse of immobilized gel,
the specific degradation of guaiacol for the agarose immobilized peroxidase increased three folds compared to that of soluble
peroxidase. Nearly 165% increase in the enzyme protein binding to agarose in presence of calcium was noted. The results suggest
that the presence of calcium, ions help in the immobilization process of peroxidase from rice shoots and mediates the direct
binding of the enzyme to the agarose gel and that agarose seems to be a better immobilization matrix for peroxidase compared
to sodium alginate. |
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Keywords: | agarose alginate calcium immobilized peroxidase Oryza sativa peroxidase |
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