Trigonelline was investigated as an NAD reserve during germination of coffee (Coffea arabica L.) seeds. Seeds were germinated on filter paper moistened with water or in agar and the endogenous content of trigonelline, nicotinic acid and NAD investigated in the endosperm, embryo and germination medium. Seeds were also fed with [carboxyl-C-14]trigonelline and the distribution of the radioactivity in these compounds was investigated, in addition, trigonelline demethylase was detected in coffee for the first time, showing a K-m of 1.13 mM. The activity increased with germination. These data clearly show that in seeds there is a significant conversion of trigonelline to NAD, although a concomitant biosynthesis of the alkaloid is also observed. It is concluded that trigonelline is indeed a reserve molecule for NAD biosynthesis but this function may be limited to the very early stages of germination or restricted to specific tissues, such as the embryo.26605611