Separate de Novo and Salvage Purine Pools Are Involved in the Biosynthesis of Theobromine but Not Caffeine in Leaves of Coffea arabica L

Nazario, Gladys M.; Lovatt, Carol J.

doi:10.1104/pp.103.4.1203

Cited by 14 publications

(6 citation statements)

References 27 publications

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“…Although the release of 14C0, from [14C]adenine was reduced greatly by 5 mM allopurinol, there was little or no significant effect on the incorporation of radioactivity into theobromine and caffeine. This observation contrasts with the findings of Nazario and Lovatt (1993b), who reported that 10 mM allopurinol treatment of Figure 4 illustrates the analysis of methanol-soluble metabolites of [8-14C]guanine by HPLC-RC. In addition to the guanine substrate, the radiolabeled compounds detected included caffeine, theobromine, 7-methylxanthine, allantoin, and allantoic acid.…”

Section: Levels Of Endogenous Xanthine Derivativescontrasting

confidence: 55%

“…They also utilized a number of "noncommitted" radiolabeled substrates such as bicarbonate, formate, and Gly, whose low leve1 incorporation into purine alkaloids, especially i n long-term experiments, may well b e a consequence of the introduction of label into the purine ring and / o r substituent methyl groups via indirect secondary pathways (Anderson a n d Gibbs, 1962). It should also be noted that Nazario a n d Lovatt (1993aLovatt ( , 1993b) used co-crystallization to identify a n d quantify radiolabeled metabolites i n highly impure plant extracts. A s a consequence, their analytical data m u s t be viewed with caution until confirmatory evidence, obtained with more rigorous methods such as HPLC o r GC-MS, is forthcoming.…”

Section: Biosynthesis Of Caffeine From [8-14c]guanine In C Arabicamentioning

confidence: 99%

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Biosynthesis of Caffeine in Leaves of Coffee

et al. 1996

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Caffeine (1,3,7-trimethylxanthine) and theobromine (3,7-dimethylxanthine) have been found in more than 60 subtropical plant species (Suzuki et al., 1992). Many plants used for nonalcoholic beverages, such as tea (Camellia sinensis L.), coffee (Coffea arabica L.), cocoa (Theobroma cacao), and maté (Ilex paraguariensis), contain these purine alkaloids (Suzuki and Waller, 1988). The biosynthesis pathway of theobromine and caffeine has been the subject of much study over the years. Although early investigations implied the involvement of nucleic acids as precursors in caffeine biosynthesis (Ogutuga and Northcote, 1970; Suzuki and Takahashi, 1976), more recent investigations with tea and coffee suggest that caffeine is produced from the purine nucleotides AMP, GMP, and/ or IMP and that theobromine is the immediate precursor of caffeine ( Fig. 1) (Negishi et al., 1985(Negishi et al., , 1992Fujimori et al., 1991;Suzuki et al., 1992;Fujimori and Ashihara, 1994). In coffee, young leaves that are not fully expanded have the highest capacity for caffeine biosynthesis (Fujimori and Ashihara, 1994).

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Section: Levels Of Endogenous Xanthine Derivativescontrasting

confidence: 55%

Section: Biosynthesis Of Caffeine From [8-14c]guanine In C Arabicamentioning

confidence: 99%

Biosynthesis of Caffeine in Leaves of Coffee

et al. 1996

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“…The metabolic pathway of purines, which family caffeine is a member of, has not been elucidated in detail, although we recently proposed major biosynthetic pathways of the purine metabolites in leaves of coffee ( Coffea arabica ) and tea ( Camellia sinensis ) [1–4]. Details of minor pathways for theobromine and caffeine are still obscure especially in coffee plants, for example, Nazario and Lovatt proposed different pathways of caffeine biosynthesis in coffee leaves [5]. Since the caffeine biosynthetic pathway contains three S ‐adenosyl‐ L ‐methionine (SAM)‐dependent methylation steps, N ‐methyltransferases play important roles.…”

Section: Introductionmentioning

confidence: 99%

Isolation of a new dual‐functional caffeine synthase gene encoding an enzyme for the conversion of 7‐methylxanthine to caffeine from coffee (Coffea arabica L.)¹

et al. 2002

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In co¡ee and tea plants, ca¡eine is synthesized from xanthosine via a pathway that includes three methylation steps. We report the isolation of a bifunctional co¡ee ca¡eine synthase (CCS1) clone from co¡ee endosperm by reverse transcriptionpolymerase chain reaction (RT-PCR) and rapid ampli¢cation of cDNA ends (RACE) technique using previously reported sequence information for theobromine synthases (CTSs). The predicted amino acid sequences of CCS1 are more than 80% identical to CTSs and are about 40% similar to those of tea ca¡eine synthase (TCS1). Interestingly, CCS1 has dual methylation activity like tea TCS1.

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“…The available data indicate that a xanthosine→7‐methylxanthosine→7‐methylxanthine→theobromine→caffeine pathway is the major route to caffeine [3,4]. However, xanthosine 5′‐monophosphate (XMP), rather than xanthosine, has also been proposed as the methyl acceptor in coffee leaves [5,6] (Fig. 1 ).…”

Section: Introductionmentioning

confidence: 99%

The first committed step reaction of caffeine biosynthesis: 7‐methylxanthosine synthase is closely homologous to caffeine synthases in coffee (Coffea arabica L.)¹

et al. 2003

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The ¢rst committed step reaction of ca¡eine biosynthesis:7-methylxanthosine synthase is closely homologous to ca¡eine synthases in co¡ee (Co¡ea arabica L.) Abstract In co¡ee and tea plants, ca¡eine is synthesized from xanthosine via a pathway that has three methylation steps. We identi¢ed and characterized the gene encoding the enzyme for the ¢rst methylation step of ca¡eine biosynthesis. The fulllength cDNA of co¡ee tentative ca¡eine synthase 1, CtCS1, previously isolated by the rapid ampli¢cation of cDNA ends was translated with an Escherichia coli expression system and the resultant recombinant protein was puri¢ed using Ni-NTA column. The protein renamed CmXRS1 has 7-methylxanthine synthase (xanthosine:S-adenosyl-L-methionine methyltransferase) activity. CmXRS1 was speci¢c for xanthosine and xanthosine 5P P-monophosphate (XMP) could not be used as a substrate. The K m value for xanthosine was 73.7 W WM. CmXRS1 is homologous to co¡ee genes encoding enzymes for the second and third methylation steps of ca¡eine biosynthesis.

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Separate de Novo and Salvage Purine Pools Are Involved in the Biosynthesis of Theobromine but Not Caffeine in Leaves of Coffea arabica L

Cited by 14 publications

References 27 publications

Biosynthesis of Caffeine in Leaves of Coffee

Biosynthesis of Caffeine in Leaves of Coffee

Isolation of a new dual‐functional caffeine synthase gene encoding an enzyme for the conversion of 7‐methylxanthine to caffeine from coffee (Coffea arabica L.)¹

The first committed step reaction of caffeine biosynthesis: 7‐methylxanthosine synthase is closely homologous to caffeine synthases in coffee (Coffea arabica L.)¹

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Separate de Novo and Salvage Purine Pools Are Involved in the Biosynthesis of Theobromine but Not Caffeine in Leaves of Coffea arabica L

Cited by 14 publications

References 27 publications

Biosynthesis of Caffeine in Leaves of Coffee

Biosynthesis of Caffeine in Leaves of Coffee

Isolation of a new dual‐functional caffeine synthase gene encoding an enzyme for the conversion of 7‐methylxanthine to caffeine from coffee (Coffea arabica L.)1

The first committed step reaction of caffeine biosynthesis: 7‐methylxanthosine synthase is closely homologous to caffeine synthases in coffee (Coffea arabica L.)1

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Isolation of a new dual‐functional caffeine synthase gene encoding an enzyme for the conversion of 7‐methylxanthine to caffeine from coffee (Coffea arabica L.)¹

The first committed step reaction of caffeine biosynthesis: 7‐methylxanthosine synthase is closely homologous to caffeine synthases in coffee (Coffea arabica L.)¹