The Biosynthesis of (+)-Tartaric Acid in Pelargonium crispum

Metabolic conversion of l-galactono-1, 4-lactone and l-ascorbic acid to (+)-tartaric acid and oxalic acid has been studied in Pelargonium crispum, cv. Prince Rupert. Experiments with specifically labeled substrates suggest a path of conversion involving cleavage of l-ascorbic acid, or a metabolic product of l-ascorbic acid, between C₂ and C₃, such that oxalic acid arises from the two carbon fragment and (+)-tartaric acid from the four carbon fragment.