MetaCyc Pathway: betanidin degradation
Inferred from experimentTraceable author statement to experimental support

Pathway diagram: betanidin degradation

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 Degradation

Some taxa known to possess this pathway include : Beta vulgaris vulgaris

Expected Taxonomic Range: Caryophyllales

General Background

The violet to red betacyanins (e.g. betacyanin biosynthesis) are a subclass of the betalains (see betalamic acid biosynthesis) and occur almost exclusively in the order of Caryophyllales [Strack03, Cai05, Grotewold06]. While the biosyntheses of betacyanins and the closely related betaxanthins (e.g. betaxanthin biosynthesis (via dopaxanthin)) are well studied, almost nothing is known about the degradative metabolization of those compounds.

About This Pathway

Soboleva and coworkers [Soboleva76] first described the enzymatically caused discoloration and breakdown of betacyanins in Beta vulgaris (garden beet) under uptake of oxygen. Since then some progress has been made to identify and characterize the enzyme with special focus on its substrate specificity [Shih81, Elliott83].

The assumption that a peroxidase may be involved in the catabolic oxidation of betacyanins has been corroborated by studying the reaction in Camellia sinensis. The peroxidase was found to oxidize both betanidin and its glucosidic derivative betanin. For the betanin oxidation the peroxidase catalyzed a reaction that yielded a intermediate cyclo-DOPA 5-O-β-D-glucoside dimer, and several oxidized cyclo-DOPA 5-O-β-D-glucoside polymers and betalamic acid [Elliott83, Martinez97].

The peroxidative oxidation of the aglycon betanidin led to the formation of betanidin quinone. The enzymatic reaction involved was to produce the betanidin radical intermediate which subsequently, by further nonenzymatic dismutation, generated betanidin quinone and betanidin. However, the further catabolism of betanidin quinone or its association with interconnecting pathways remains to be studied in more detail. The peroxidase has been classified as a class III peroxidase located in the vacuole. The much lower efficiency of the peroxidase towards betacyanin glucosides and the known vacuolar localization of β-glucosidases were discussed as interactions of both enzymes indicating a metabolic role of this peroxidase(s) in the metabolization of betacyanins [MartinezParra01].

Created 19-Jan-2007 by Foerster H, TAIR


Cai05: Cai Y, Sun M, Corke H (2005). "HPLC characterization of betalains from plants in the amaranthaceae." J Chromatogr Sci 43(9);454-60. PMID: 16212790

Elliott83: Elliott DC, Schultz CG, Cassar R (1983). "Betacyanin decolourizing enzyme in Amaranthus tricolor seedlings." Phytochemistry, 22(2), 383-387.

Grotewold06: Grotewold E (2006). "The genetics and biochemistry of floral pigments." Annu Rev Plant Biol 57;761-80. PMID: 16669781

Martinez97: Martinez Parra J, Munoz R (1997). "An Approach to the Characterization of Betanine Oxidation Catalyzed by Horseradish Peroxidase." J. Agric. Food Chem. 45, 2984-2988.

MartinezParra01: Martinez-Parra J, Munoz R (2001). "Characterization of betacyanin oxidation catalyzed by a peroxidase from Beta vulgaris L. roots." J Agric Food Chem 49(8);4064-8. PMID: 11513711

Shih81: Shih CC, Wiley RC (1981). "Betacyanine and betaxanthine decolorizing enzymes in the beet (Beta vulgaris L.) roots." J. Food Sci., 47, 164-199.

Soboleva76: Soboleva GA, Ul'ianova MS, Zakharova NS, Bokuchava MA (1976). "[Study of betacyanin-discolorating enzyme]." Biokhimiia 41(6);968-74. PMID: 17435

Strack03: Strack D, Vogt T, Schliemann W (2003). "Recent advances in betalain research." Phytochemistry 62(3);247-69. PMID: 12620337

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 SRI International Pathway Tools version 19.5 on Mon Nov 30, 2015, BIOCYC13B.