Biosynthesis of vitamin C during germination. Part III. Effects of sugars, Krebs' intermediates, amino acids and B vitamins and correlation with biogenesis of nicotinic acid

Abstract

(1) Further observations on the effects of certain cultural and environmental factors on biosynthesis of ascorbic acid in germinating seeds of müng (Phaseolus radiatus) are reported. Seed embryos separated from the reserve food store in cotyledons and grown on a semi-solid nutrient medium have been employed in some of these studies. Concomitant changes in nicotinic acid have been also followed. (2) In confirmation of earlier work, hexoses, particularly, glucose and mannose, have a pronounced enhancing effect on ascorbic acid formation. (3) Certain intermediates of carbohydrate metabolism such as citrate, succinate, fumarate and malate, induce increased synthesis of vitamin C; the effects of succinate and fumarate are noteworthy. (4) Thiamine, riboflavin, nicotinic acid and biotin stimulate ascorbic acid elaboration. (5) Accelerating effects are also noted with tryptophane, tyrosine, serine and glycine. (6) A parallelism between the biogeneses of ascorbic and nicotinic acids, under various cultural treatments is observed. (7) The possible implications of these observations have been discussed indicating probable involvement of hexose intermediates in ascorbic acid synthesis.