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Arch Biochem Biophys. 1990 Feb 1;276(2):390-5.

Phytoalexin synthesis in soybean: purification and characterization of NADPH:2'-hydroxydaidzein oxidoreductase from elicitor-challenged soybean cell cultures.

Author information

1
Lehrstuhl für Biochemie der Pflanzen, Biologisches Institute II, Universität Freiburg, Federal Republic of Germany.

Abstract

An NADPH:2'-hydroxydaidzein oxidoreductase (HDR) from elicitor-challenged soybean cell cultures was purified to apparent homogeneity by a five-step procedure. The purification procedure included affinity adsorption on Blue Sepharose and elution of the enzyme with NADP+. It was shown by gel filtration and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis that HDR consists of only one polypeptide, which has a Mr about 34,700. The pH optimum of the reaction was 7.0. Apparent Michaelis constants determined for 2'-hydroxydaidzein, 2'-hydroxyformononetin, and NADPH were, respectively, 50, 60, and 56 microM. A low conversion of 2'-hydroxygenistein to the corresponding isoflavanone was also observed but isoflavones lacking a 2'-hydroxyl group and various other flavonoids did not serve as substrates. Enzymatically derived 2'-hydroxydihydrodaidzein gave a positive CD spectrum at 328 nm, which shows its 3R stereochemistry. Antibodies against HDR were raised in rats.

PMID:
2306102
DOI:
10.1016/0003-9861(90)90737-j
[Indexed for MEDLINE]

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