Stability of Vitamins in a Chemically Defined Medium for 929-L Fibroblasts2

Abstract
Thiamine and ascorbic acid, but not riboflavine or choline, were unstable in Waymouth's medium, MB 752/1, stored at 4° or incubated at 36°. Growth of cells in medium at 36°C caused no more loss of vitamin content than did incubation of medium without cells. Ascorbic acid decomposed to products other than dehydroascorbic and diketogulonic acids. Thiamine was converted, at least in part, to a disulfide, which, like homomeric thiamine disulfide, was rapidly reduced by cells to free thiamine.