BIOSYNTHESIS OF THEOBROMINE AND CAFFEINE IN DEVELOPING LEAVES OF COFFEA-ARABICA

The levels of purine alkaloids and the metabolism of [8-C-14]adenine in the first (small) and the second (almost fully developed) leaves from the shoot apices of coffee plants were examined. Theobromine and caffeine were found in these leaves, but no theophylline was detected. [8-C-14]Adenine was taken up by segments of the first and the second leaves, and was converted to nucleotides and nucleic acids. Conversion of [8-C-14]adenine to theobromine and caffeine was found only in the first leaves. More than half of the radioactivity taken up by the young leaves was distributed among purine alkaloids after 24 hr of the administration. The extent of degradation of adenine nucleotides by the conventional purine catabolic pathway was low in both leaves.