PURIFICATION AND CHARACTERIZATION OF THE QUINATE - OXIDOREDUCTASE FROM PHASEOLUS-MUNGO SPROUTS

Autor(en): KANG, XB
SCHEIBE, R 
Stichwörter: Biochemistry & Molecular Biology; DEHYDROQUINIC ACID; ENZYME PURIFICATION; FABACEAE; MUNGBEAN; NAD+ OXIDOREDUCTASE; PHASEOLUS-MUNGO; Plant Sciences; PROTEIN; QUINATE-OXIDOREDUCTASE; QUINIC ACID; SEEDLINGS; SHIKIMATE PATHWAY
Erscheinungsdatum: 1993
Herausgeber: PERGAMON-ELSEVIER SCIENCE LTD
Journal: PHYTOCHEMISTRY
Volumen: 33
Ausgabe: 4
Startseite: 769
Seitenende: 773
Zusammenfassung: 
A quinate:oxidoreductase which catalyses the interconversion of (-)-quinic acid and 3-dehydroquinic acid, was extracted from the homogenate of Phaseolus mungo sprouts bought from a supermarket and purified by ammonium sulphate fractionation, anion exchange (DEAE-cellulose), hydrophobic interaction (Phenyl-Sepharose), affinity (Blue Sepharose) chromatography and gel filtration (FPLC Superose 12). Unlike most quinate:oxidoreductases of higher plants reported, which are absolutely NAD(H) specific, the enzyme from mungbean sprouts can use both NAD(H) and NADP(H) as a cofactor. Although the K(m)-values for NAD(H) and NADP(H) differ by one order of magnitude, no difference between the apparent maximum activities with NAD(H) and NADP(H) as cofactors is observed. The purified enzyme has a specific activity of about 0.5 mukat mg-1 protein (quinic to 3-dehydroquinic acid, pH 9.8, NAD) and 2.83 mukat mg -1 protein (3-dehydroquinic to quinic acid, pH 8.2, NADH). Upon gel filtration the enzyme has a M(r) of 160 000. SDS- PAGE of the peak fraction results in a single protein band of about 55 000. This result suggests that the enzyme might be a trimer.
ISSN: 00319422
DOI: 10.1016/0031-9422(93)85272-S

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