The uptake of adenine by brewers' yeast and a respiratory-deficient mutant

Abstract

On suspending “resting” cells of a strain of brewing yeast and of a derived respiratory-deficient mutant in an adenine-containing medium, there resulted no ultimate concentration of free adenine within the cells although the total concentration of adenine derivatives increased when glucose or certain other carbohydrates were incorporated into the medium. The increase resulted from a stimulation of the conversion of the adenine into nucleotides. After keeping in the presence of adenine and glucose and then transferring to a medium free of glucose, the yeasts released hypoxanthine and not adenine, even though adenine was present within the cells in a form soluble in cold trichloroacetic acid. There was no evidence that the uptake of adenine by these yeasts was dependent upon a specific concentrating mechanism as is the case for certain carbohydrates. It appears rather that the linkage between uptake of adenine and glucose metabolism is due to combination of the purine with a dissimilation product of glucose, possibly 5-phosphoribosyl-1-pyrophosphate, to form nucleotides.