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.Abbreviation AA l-Ascorbic Acid