MetaCyc Pathway: caffeine degradation I (main, plants)
Inferred from experimentAuthor statement

Enzyme View:

Pathway diagram: caffeine degradation I (main, plants)

This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.

Superclasses: Degradation/Utilization/AssimilationSecondary Metabolites DegradationNitrogen Containing Secondary Compounds DegradationAlkaloids DegradationCaffeine Degradation

Some taxa known to possess this pathway include : Camellia irrawadiensis, Camellia ptilophylla, Camellia sinensis, Coffea arabica, Coffea eugenioides

Expected Taxonomic Range: Camellia, Coffea, Theobroma

General Background

Caffeine is found in several plant species including coffea, tea and cacao. The contents of caffeine vary greatly from cultivar to cultivar, tissue to tissue, and from different developmental stages. One mechanism that plants use to control caffeine level is by balancing between caffeine biosynthesis and degradation. The main caffeine degradation pathway has been proposed to proceed via theophylline and 3-methylxanthine, which is depicted here. In addition to the main caffeine degradation pathway, minor plant species-specific degradation pathways have also been proposed. All the proposed pathways were based on radio-tracer studies (reviewed in [Ashihara08, Mazzafera04]). No enzyme activity has been detected or characterized to date.

About This Pathway

In this main caffeine degradation pathway, caffeine is degraded by sequential removal of the three methyl groups, resulting in the formation of xanthine. Xanthine is further degraded to CO2 and NH3 via purine degradation ( purine nucleotides degradation I (plants)). C14 labeled theophylline was degraded to CO2 far more rapidly than C14 labeled caffeine, indicating the first step of the pathway is the rate-limiting step [Ito97].

Variants: caffeine degradation II, caffeine degradation III (bacteria, via demethylation), caffeine degradation IV (bacteria, via demethylation and oxidation), caffeine degradation V (bacteria, via trimethylurate)

Created 20-Jul-2010 by Zhang P, TAIR


Ashihara08: Ashihara H, Sano H, Crozier A (2008). "Caffeine and related purine alkaloids: biosynthesis, catabolism, function and genetic engineering." Phytochemistry 69(4);841-56. PMID: 18068204

Ashihara96: Ashihara, H, Monteiro, AM, Moritz, T, Gillies, FM, Crozier, A (1996). "Catabolism of caffeine and related purine alkaloids in leaves of Coffea arabica L." Planta 198:334-339.

Ashihara97: Ashihara, H, Gillies, FM, Crozier, A (1997). "Metabolism of caffeine and related purine alkaloids in leaves of tea (Camellia sinensis L.)." Plant Cell Physiology 38:413-419.

Ito97: Ito E, Crozier A, Ashihara H (1997). "Theophylline metabolism in higher plants." Biochim Biophys Acta 1336(2);323-30. PMID: 9305805

Mazzafera04: Mazzafera P (2004). "Catabolism of caffeine in plants and microorganisms." Front Biosci 9;1348-59. PMID: 14977550

Other References Related to Enzymes, Genes, Subpathways, and Substrates of this Pathway

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by Pathway Tools version 19.5 (software by SRI International) on Sun Nov 29, 2015, biocyc14.