Biosynthesis of Vitamin G: A New Precursor

Abstract

The condensation product (I) of glucose and ethylacetoacetate (2-tetra-hydroxybutyl-5-methyl 4-carbethoxy furan), which is structurally similar to ascorbic acid, was found to be a new precursor of ascorbic acid when added to the medium for the germination of mung beans. (I) was also found to raise the ascorbic acid level in the plasma of rats. The transformation of (I) to vit. C (II) was discussed. An acceleration in the biosynthesis of vit. C was also observed when glucose and acetoacetate are present in equimolecular amts. Glucose was found to prevent the harmful effect of acetoacetate with respect to depletion of ascorbic acid in vivo as well as during the germination of mung beans (thus suggesting new pathways of glucose metabolism not previously recognized). The work may throw some light on the mechanism of the biosynthesis of vit. C (II) from hexose sugars and lipids, and thereby give more wt. to the concept of a metabolic relationship between glucose and acetoacetate already discovered in our laboratory.