Purification and characterization of a polyphenol oxidase from the seeds of field bean (Dolichos lablab).
IR@CFTRI: CSIR-Central Food Technological Research Institute, Mysore
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http://ir.cftri.com/2152/
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| Title |
Purification and characterization of a polyphenol oxidase from the seeds of field bean (Dolichos lablab).
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| Creator |
Paul, B.
Gowda, L. R. |
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| Subject |
22 Legumes-Pulses
16 Enzyme Chemistry |
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| Description |
The polyphenol oxidase from field bean (Dolichos lablab) seeds has been purified to apparent homogeneity by a combination of ammonium sulfate precipitation, DEAE-Sephacel chromatography, phenyl agarose chromatography, and Sephadex G-200 gel filtration. The purified enzyme has a molecular weight of 120 +/- 3 kDa and is a tetramer of 30 +/- 1.5 kDa. Native polyacrylamide gel electrophoresis of the purified enzyme revealed the presence of a single isoform with an observed pH optimum of 4.0. 4-Methyl catechol is the best substrate, followed by catechol, and L-3,4-dihydroxyphenylalanine, all of which exhibited a phenomenon of inhibition by excess substrate. No activity was detected toward chlorogenic acid, catechin, caffeic acid, gallic acid, and monophenols. Tropolone, both a substrate analogue and metal chelator, proved to be the most effective competitive inhibitor with an apparent K(i) of 5.8 x 10(-)(7) M. Ascorbic acid, metabisulfite, and cysteine were also competitive inhibitors.
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| Date |
2000
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Language |
en
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—
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| Identifier |
http://ir.cftri.com/2152/1/J._Agric._Food_Chem.%2C_2008%2C_48_%289%29%2C_pp_3839%E2%80%933846.pdf
Paul, B. and Gowda, L. R. (2000) Purification and characterization of a polyphenol oxidase from the seeds of field bean (Dolichos lablab). Journal of agricultural and food chemistry, 48 (9). pp. 3839-3846. ISSN 0021-8561 |
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