Conversion of L-sorbosone to L-ascorbic acid by a NADP-dependent dehydrogenase in bean and spinach leaf. [Phaseolus vulgaris L. ; Spinacia oleracea L]

Journal Article · Thu Nov 01 00:00:00 EST 1990 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.94.3.1492· OSTI ID:5629189

Loewus, M W; Bedgar, D L; Saito, Kazumi; Loewus, F A ^[1]

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1. Washington State Univ., Pullman (USA)

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 {minus}20{degree}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{sub m} for sorbosone were 12 {plus minus} 2 and 18 {plus minus} 2 millimolar and for NADP{sup +}, 0.14 {plus minus} 0.05 and 1.2 {plus minus} 0.5 millimolar, for bean and spinach, respectively. Lycorine, a purported inhibitor of L-ascorbic acid biosynthesis, had no effect on the reaction.

• OSTI ID: 5629189
• Journal Information: Plant Physiology; (USA), Vol. 94:3; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ASCORBIC ACID
BIOSYNTHESIS
PHASEOLUS
PHYSIOLOGY
SPINACH
METABOLISM
NADP
OXIDOREDUCTASES
SORBOSE
CARBOHYDRATES
COENZYMES
ENZYMES
FOOD
HEXOSES
KETONES
LEGUMINOSAE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MONOSACCHARIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
PLANTS
SACCHARIDES
SYNTHESIS
VEGETABLES
VITAMINS
550200* - Biochemistry