Localization of the carbon in caffeine biosynthesized fromN-methyl carbon ofγ-glutamylmethylamide in tea plants

摘要

1. Localization of carbon in caffeine molecule biosynthesized from theN-methyl carbon ofγ-glutamylmethylamide in tea plants was observed.14C-Caffeine produced from14C-γ-glutamylmethylamide was isolated and degraded. Approximately 26–55of the14C was observed in the three methyl carbons in caffeine, with only 2–3at the C-2 carbon, 3–7at the C-8 carbon position. The amount of14C at the C-4, C-5 and C-6 positions was calculated from the results obtained.2. The role of theN-methyl carbon ofγ-glutamylmethylamide in the formation of RNA in tea plants was examined. Incorporation of theN-methyl-14C of14C-γ-glutamylmethylamide into AMP and GMP in RNA was found.These facts indicate that in tea plants,γ-glutamylmethylamide is metabolized and most of itsN-methyl carbon is utilized as a precursor for caffeine formation and little, if any, as a precursor for nucleic acid