Extraction and characterization of an indole oxidizing enzyme in Vitis leaves
An indole oxidase from leaves of Vilis vinifera L. was isolated and purified to homogeneity. The purifieded enzyme (Mw 65,000) catalysed the conversion of indole into anthranilic acid, with 5-methylindole, 5-bromoindole and 5-hydroxyindole, also being used as substrates. Km value for the indole was 0.125 mM. The optimum pH for the reaction was 5.0. The ufilization of indole by the enzyme did not require L-serine or pyridoxal phosphate, and did not result in net tryptophan synthesis. The activity was inhibited by both sulfhydryl reagents and sulfhydryl compounds, by specific chelators of copper and non-heme iron (Fe2+), dithionite and atebrin. Atebrin inhibition could be prevented by FAD. Dialysis resulted in complete loss of enzyme activity, and the dialyzed inactive enzyme could be reactivated by the simultaneous addition of Cu2+, Fe2+ and FAD. The data suggest that this indole oxidase is an ironcuproflavoprotein.
| Main Authors: | , |
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| Format: | artículo biblioteca |
| Language: | English |
| Published: |
Firenze University Press
1995
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| Online Access: | http://hdl.handle.net/10261/58438 |
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