Biosynthesis and metabolism of L-ascorbic acid in virginia creeper (Parthenocissus quinquefolia L.).

Detached leaves of Parthenocissus quinquefolia L., Vitaceae convert D-glucose to L-ascorbic acid with conservation of the carbon chain sequence and with retention of the hydroxymethyl group at carbon 6. L-Ascorbic acid is cleaved between carbons 4 and 5. The C4 fragment is converted to L-tartaric acid. The C2 fragment, possibly glycolaldehyde, recycles into products of hexose phosphate metabolism. During the metabolic period a relatively high portion of carbon-1 of L-ascorbic acid, as compared with carbon-4, was released as CO2. These studies demonstrate the usefulness of Virginia Creeper for yeararound research on ascorbic-acid metabolism and tartaric-acid biosynthesis in Vitaceae-type plants.