Vorkommen von Theophyllin in Kakaobohnen

Franzke, Cl.; Griehl, H.; Grunert, Stefan; Hollstein, E.

doi:10.1007/bf00591716

Cited by 10 publications

(3 citation statements)

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“…These observations are consistent with those made on caffeine biosynthesis by using the intact plants or callus tissue of tea plants (Ogutuga & Northcote, 1970a,b;Suzuki, 1973;Suzuki &Takahashi, 1974), and are further supported by the facts that theobromine and caffeine are normal constituents of the leaves both of intact and manufactured plants, i.e. green and black tea (Franzke et al, 1968). In addition, from our present results (Table 3), the formation of theophylline, which is also found in tea leaves (Franzke et al, 1968), is explained as the result of the methylation of 1-methylxanthine rather than that of 3-methylxanthine.…”

Section: Discussionsupporting

confidence: 88%

“…green and black tea (Franzke et al, 1968). In addition, from our present results (Table 3), the formation of theophylline, which is also found in tea leaves (Franzke et al, 1968), is explained as the result of the methylation of 1-methylxanthine rather than that of 3-methylxanthine. Thus the hypothesis that theophylline is synthesized from xanthine via 3-methylxanthine (Ogutuga & Northcote, 1970b) seems to be unlikely.…”

Section: Discussionmentioning

confidence: 99%

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Biosynthesis of caffeine by tea-leaf extracts. Enzymic formation of theobromine from 7-methylxanthine and of caffeine from theobromine

Suzuki

Takáhashi

1975

Biochemical Journal

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1. Extracts prepared from tea leaves with Polyclar AT (insoluble polyvinylpyrrolidine) contained two methyltransferase activities catalysing the transfer of methyl groups from S-adenosylmethionine to 7-methylxanthine, producing theobromine, and to theobromine, producing caffeine. 2. The methyltransferases exhibited the same pH optimum (8.4) and a similar pattern of effects by metal ions, thiol inhibitors and metal-chelating reagents, both for theobromine and caffeine synthesis. Mg2+, Mn2+ and Ca2+ slightly stimulated enzyme activity but they were not essential. Paraxanthine was shown to be most active among methylxanthines, as the methyl acceptor. However, the formation of paraxanthine from 1-methylxanthine was very low and that from 7-methylxanthine was nil, suggesting that the synthesis of caffeine from paraxanthine is of little importance in intact plants. Xanthine, xanthosine, XMP and hypoxanthine were all inactive as methyl acceptors, whereas [2(-14)C]xanthine and [8(-14)C]hypoxanthine were catabolized to allantoin and urea by tea-leaf extracts. The apparent Km values are as follows: 7-methylxanthine, 1.0 times 10(-14)M; theobromine, 1.0 times 10(-3)M; paraxanthine, 0.2 times 10(-3)M; S-adenosylmethionine, 0.25 times 10(-4)M (with each of the three substrates). 3. The results suggest that the pathway for caffeine biosynthesis is as follows: 7-methylxanthine leads to theobromine leads to caffeine. In contrast, it is suggested that theophylline is synthesized from 1-methylxanthine. The methyl groups of the purine ring of caffeine are all derived directly from the methyl group of S-adenosylmethionine. Little is known about the pathways leading to the formation of 7-methylxanthine. 4. A good correlation between caffeine synthesis and shoot formation or growth of tea seedlings was shown, suggesting that the methylating systems in caffeine synthesis are closely associated with purine nucleotide and nucleic acid metabolism in tea plants.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionmentioning

confidence: 99%

Biosynthesis of caffeine by tea-leaf extracts. Enzymic formation of theobromine from 7-methylxanthine and of caffeine from theobromine

Suzuki

Takáhashi

1975

Biochemical Journal

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“…Caffeine (1,3,7-trimethylxanthine) is a major alkaloid of coffee, tea, cola, and guaraña (Weevers, 1930), and other methylxanthines, e.g., theobromine (3,7-dimethylxanthine) and theophylline (1,3-dimethylxanthine), are found as minor components in these plants (Maravalhas, 1966;Franzke et al, 1968;Tabak et al, 1969). In vivo and in vitro studies with tea and coffee plants have shown that theobromine is synthesized from 7-methylxanthine and transformed to caffeine Takahashi, 1975, 1976a,b;Ogutuga and Northcote, 1970a,b; Looser et al, 1974;Roberts and Waller, 1979;Waller et al, 1981).…”

mentioning

confidence: 99%