Isolation of d-glyceric acid from cress seedlings and its relationship to the synthesis of l-ascorbic acid

Publisher Website
Google Scholar
Abstract
Cress seedlings cultured for 3-5 days in the dark at 20[degree] were shown by chromatographic methods to contain from 0.05 to 0.5% of D-glyceric acid/g. fresh weight. Quantitative studies of the amt. of D-glyceric and L-ascorbic acids present throughout the period of growth of the seedling (up to 5 days) in various nutrient solns. (0.04 [image] sodium bicarbonate, water and 0.02[image] ammonium sulphate) have shown that the formation of each runs roughly parallel. This is also true when seedlings cultured in water are subjected to changes in temperature during their growth. Feeding D-glucurono-and L-gulono- [gamma] -lactones, which are known to be precursors of L-ascorbic acid, to cress seedlings definitely depressed the formation of D-glyceric acid. A somewhat similar relationship to that observed in the cress seedling between the formation of D-glyceric and L-ascorbic acids possibly exists in the rat, for treatment with the drug chloretone causes the rat to excrete in its urine increased amounts of both D-glyceric and L-ascorbic acids. It is clear, however, that D-glyceric acid is not a direct precursor of L-ascorbic acid, since feeding the ethyl ester of D-glyceric acid (the ester was used as a convenient method of introducing D-glyceric acid into the cell) to cress seedlings or injecting it into the rat did not increase the formation of L-ascorbic acid. The connexion between the synthesis of D-glyceric acid and the synthesis of L-ascorbic acid remains obscure.