Conversion of l-Sorbosone to l-Ascorbic Acid by a NADP-Dependent Dehydrogenase in Bean and Spinach Leaf
- 1 November 1990
- journal article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 94 (3) , 1492-1495
- https://doi.org/10.1104/pp.94.3.1492
Abstract
An NADP-dependent dehydrogenase catalyzing the conversion of l-sorbosone to l-ascorbic acid has been isolated from Phaseolus vulgaris L. and Spinacia oleracea L. and partially purified. It is stable at -20 degrees C for up to 8 months. Molecular masses, as determined by gel filtration, were 21 and 29 kilodaltons for bean and spinach enzymes, respectively. K(m) for sorbosone were 12 +/- 2 and 18 +/- 2 millimolar and for NADP(+), 0.14 +/- 0.05 and 1.2 +/- 0.5 millimolar, for bean and spinach, respectively. Lycorine, a purported inhibitor of l-ascorbic acid biosynthesis, had no effect on the reaction.Keywords
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