STUDIES ON THE METABOLIC CONTROL OF CAFFEINE TURNOVER IN DEVELOPING ENDOSPERMS AND LEAVES OF COFFEA-ARABICA AND COFFEA-DEWEVREI

Leaves and immature fruits of Coffea deweurei and Coffea arabica var. Mundo Novo and var. Laurina were fed with [8-H-3]caffeine and the products analyzed by reversed-phase high-performance liquid chromatography with ultraviolet and radioactivity detection. In fruits, only endosperms were analyzed. In addition, the activities of two methyltransferases involved in the biosynthesis of caffeine were studied in cell-free preparations from leaves and endosperms. The results provide evidence that the low caffeine content in leaves and endosperms of immature fruits of C. dewevrei may be due to slow biosynthesis and fast degradation. The high caffeine content in leaves and endosperms of C. arabica seems to be a consequence of a rapid rate of production coupled with a slow degradation rate.