Читать книгу Plant Nucleotide Metabolism - Hiroshi Ashihara - Страница 15

As shown in structure 1 the atoms of the purine ring are numbered in an anticlockwise manner. In plants, there are several naturally occurring purine bases. They include adenine (2) and guanine (3), which are constituents of nucleic acids, and hypoxanthine (4), xanthine (5), and uric acid (6), which are produced as catabolites of adenine and guanine. Purine alkaloids, such as theobromine (3,7-dimethylxanthine) (7), theophylline (1,3-dimethylxanthine) (8), caffeine (1,3,7-trimethylxanthine) (9), and theacrine (1,3,7,9-tetramethyluric acid) (10) are derived from purine nucleotides, as are the major cytokinin plant hormones isopentenyladenine (11), benzyladenine (12), and trans-zeatin (13) (Ashihara et al. 2013).