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:||Biosynthesis → Secondary Metabolites Biosynthesis → Phenylpropanoid Derivatives Biosynthesis → Flavonoids Biosynthesis → Anthocyanins Biosynthesis|
Expected Taxonomic Range: Spermatophyta
Almost all vascular plants possess basic, water soluble anthocyanins such as delphinidin-3-O-glucoside (this pathway) responsible for the blue coloration of flowers and fruits and/or pelargonidin-3-O-glucoside and cyaniding-3-O-glucoside (anthocyanin biosynthesis (cyanidin 3-O-glucoside)) generating red to magenta colors in the floral organs of plants [Harborne00].
Anthocyanins play important roles as pigments of flowers and fruits in numerous plants across the plant kingdom to attract insects for pollination and seed dispersion and act as protectants against UV-B irradiation [Kong03]. They also exhibit anti-oxidant activities and therefore may serve as potential anticancer [Cooke05] and anti-arteriosclerosis compounds in human health [Williams04b] [Springob03] [WinkelShirley02]. Anthocyanines constitute biological active metabolites that also modulate inter-species relationships being intimately connected with the co-existence of plants with, e.g. insects, mammals, and birds [Whiting01].
About This Pathway
As described for the biosynthesis of pelargonidin- (see anthocyanin biosynthesis (pelargonidin 3-O-glucoside) and cyanidin-derived (see anthocyanin biosynthesis (cyanidin 3-O-glucoside)) anthocyanins delphinidin-based pigments are built up in a series of two enzymes, the anthocyanidin synthase (ANS - synonym leucoanthocyanidin dioxygenase - LDOX) converting leucodelphinidin to delphinidin and the UDPG: flavonoid 3-O-glucosyltransferase (3-UGT) producing the first stable anthocyanin of this pathway, i.e. delphinidin 3-O-glucoside [Kitamura06] (for a more comprehensive comment see - anthocyanin biosynthesis (cyanidin 3-O-glucoside)).
The anthocyanidin synthase has been proposed to be a component of a macromolecular complex located at the endoplasmatic reticulum. In dependence on the enzymes involved in the complex (e.g. flavonoid 3',5'-hydroxylase) and their metabolic order the ANS is involved in the production of delphinidin-derived pigments as found in bilberry [Jaakola02] and recombinant petunia ANS expressed with 3-UGT in Escherichia coli [Nakajima01]. However, specific data addressing this reaction with regard to kinetic parameter and substrate specificity remain to be reported.
The flavonoid 3-O-glucosyltransferases involved in this pathway have been found to cover a broader spectrum of anthocyanidins with a somewhat higher affinity towards delphinidin in Vitis vinifera [Ford98] and Gentiana triflora [Tanaka96c] representing species containing delphinidin-derived anthocyanins.
Cooke05: Cooke D, Steward WP, Gescher AJ, Marczylo T (2005). "Anthocyans from fruits and vegetables--does bright colour signal cancer chemopreventive activity?." Eur J Cancer 41(13);1931-40. PMID: 16084717
Ford98: Ford CM, Boss PK, Hoj PB (1998). "Cloning and characterization of Vitis vinifera UDP-glucose:flavonoid 3-O-glucosyltransferase, a homologue of the enzyme encoded by the maize Bronze-1 locus that may primarily serve to glucosylate anthocyanidins in vivo." J Biol Chem 273(15);9224-33. PMID: 9535914
Jaakola02: Jaakola L, Maatta K, Pirttila AM, Torronen R, Karenlampi S, Hohtola A (2002). "Expression of genes involved in anthocyanin biosynthesis in relation to anthocyanin, proanthocyanidin, and flavonol levels during bilberry fruit development." Plant Physiol 130(2);729-39. PMID: 12376640
Nakajima01: Nakajima J, Tanaka Y, Yamazaki M, Saito K (2001). "Reaction mechanism from leucoanthocyanidin to anthocyanidin 3-glucoside, a key reaction for coloring in anthocyanin biosynthesis." J Biol Chem 276(28);25797-803. PMID: 11316805
Tanaka96c: Tanaka Y, Yonekura K, Fukuchi-Mizutani M, Fukui Y, Fujiwara H, Ashikari T, Kusumi T (1996). "Molecular and biochemical characterization of three anthocyanin synthetic enzymes from Gentiana triflora." Plant Cell Physiol 37(5);711-6. PMID: 8819318
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