Purification and characterization of a NADPH-dependent aldehyde reductase from mung bean that detoxifies eutypine, a toxin from Eutypa lata
Eutypine (4-hydroxy-3-[3-methyl-3-butene-1-ynyl] benzaldehyde) is a toxin produced by Eutypa lata, the causal agent of eutypa dieback in the grapevine (Vitis vinifera). Eutypine isenzymatically converted by numerous plant tissues into eutypinol (4-hydroxy-3-[3-methyl-3-butene-1-ynyl] benzyl alcohol)...
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Veröffentlicht in: | Plant physiology (Bethesda) 1999-02, Vol.119 (2), p.621-626 |
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Sprache: | eng |
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Zusammenfassung: | Eutypine (4-hydroxy-3-[3-methyl-3-butene-1-ynyl] benzaldehyde) is a toxin produced by Eutypa lata, the causal agent of eutypa dieback in the grapevine (Vitis vinifera). Eutypine isenzymatically converted by numerous plant tissues into eutypinol (4-hydroxy-3-[3-methyl-3-butene-1-ynyl] benzyl alcohol), a metabolite that is nontoxic to grapevine. We report a four-step procedure for the purification to apparent electrophoretic homogeneity of a eutypine-reducing enzyme (ERE) from etiolated mung bean (Vigna radiata) hypocotyls. The purified protein is a monomer of 36 kD, uses NADPH as a cofactor, and exhibits a Km value of 6.3 micromolars for eutypine and a high affinity for 3- and 4-nitro-benzaldehyde. The enzyme failed to catalyze the reverse reaction using eutypinol as a substrate. ERE detoxifies eutypine efficiently over a pH range from 6.2 to 7.5. These data strongly suggest that ERE is an aldehyde reductase that could probably be classified into the aldo-keto reductase superfamily. We discuss the possible role of this enzyme in eutypine detoxification. |
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ISSN: | 0032-0889 1532-2548 |
DOI: | 10.1104/pp.119.2.621 |