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
The superpathway of anthocyanin biosynthesis that originates from pelargonidin 3-O-glucoside comprises the formation of compounds such as salvianin, anthocyanidin sophoroside and pelargondin conjugates. Those anthocyanins contribute to the wide variation of flower colors in various species being likewise attractive for pollinating insects and floriculturists.
Salvianin, the predominant anthocyanin causing the scarlet flower coloration of Salvia splendens has two malonyl groups linked to the 4" and 6"-hydroxyl groups of the 5-glucosyl moiety [Lu02, Kondo89]. Its biosynthesis represents a species-specific variety of the decoration of pelargonin that involves glucosylation and aromatic and aliphatic acylation to increase stability, solubility and color variation of the chromophoric anthocyanins [Yamazaki99, YonekuraSakakib00, Heller94].
Anthocyanins are produced in two distinguished sets of reactions, the first one (early-stage) leading to the first stable anthocyanidin, i.e. anthocyanidin-3-O-glucosides and the second one (late-stage) comprising further modification of those compounds such as glycosylation, acylation and methylation. These late-stage reactions are concerned with fine adjustment for a variety of floral color which is diverse and less understood than the steps involved in the early-stage reactions [Yamazaki99] [YonekuraSakakib00]. The decoration of pelargonidin is typical for a variety of plants such as Perilla frutescens, Glandularia x hybrida, Silene dioica [Yamazaki99] and Dahlia pinnata [Suzuki02a]. Many of the above mentioned plants are characterized by anthocyanins that are intermediately 5-O-glucosylated. Anthocyanidins often occur as sophoroside, i.e. a diglucoside that consists of glucose attached to the 2''-O-position of the 3-O-glucose moiety of anthocyanidins. The anthocyanidin that confers the bright blue color to Ipomoea nil (a member of the Convolvulacea) is a sophoroside that forms a complex with several caffeoyl residues, known as Wedding Bells anthocyanin (HBA). Reddish-brown flowers of dusky mutants of Ipomoea nil contain Heavenly Blue antocyanin (WBA) representing the most favorite flower hue for Japanese floriculturists [Morita05].
About This Pathway
Salvianin: Pelargonidin 3-O-β-D-glucoside represents the starting compound that is stepwise converted into bisdemalonylsalvianin, the precursor for the aliphatic acylation with malonyl-CoA. Those reactions involve 5-O-glucosylation [Yamazaki99] and 3-aromatic acylation with caffeic acid [Fujiwara98] [YonekuraSakakib00] which may proceed via two parallel pathway branches. Bisdemalonylsalvianin is further malonylated twice on its 5-O-glucosidic moiety which is carried out by two different regio-specific malonyltransferases [Suzuki01a] [Suzuki04a].
Pelargonidin conjugates: The 5-O-glucosylation of anthocyanidin-3-O-glucosides, catalyzed by the anthocyanin 5-O-glucosyltransferase (5-GT) does not significantly change the color of anthocyanins but is important for further modification of anthocyanin molecules [Yamazaki02, Yamazaki99]. A significant contribution to intensification of color and color shift towards blue is accomplished by aromatic acylation with hydroxycinnamic acids of the anthocyanin molecules due to a bathochromic shift. The enzyme catalyzing this step, anthocyanin 3-O-glucoside-6"-O-acyltransferase has been characterized in Perilla frutescens [Fujiwara98] [YonekuraSakakib00]. The exact metabolic succession of aromatic acylation (C-ring 3-position, A-ring 5-position) of the anthocyanin glucosides (mono-, diglucoside) is not known and may depend on the species involved. The malonylation of anthocyanins, for instance catalyzed by the anthocyanidin 3-O-glucoside-6"-O-malonyltransferase [Suzuki02a] generally occurs under strict regiocontrol during the late stage of their biosynthesis. Other modifications of the anthocyanins involve further glycosylations catalyzed by anthocyanidin 3-O-glucoside-6"-O-rhamnosyltransferase [Kamsteeg80] and anthocyanidin 3-O-rutinoside-5-O-glucosyltransferase [Kamsteeg78].
Anthocyanin sophoroside: The crucial step in the formation of anthocyanidin sophoroside as precursors for HBA and WBA in Ipomoea is catalyzed by the anthocyanidin 3-O-glucoside 2-O''-glucosyltransferase (3GGT). The enzyme adds glucose to anthocyanidin 3-glucosides at the 2''-O-position of the glucose moiety forming the corresponding sophorosides. Although the enzyme accepts all three major anthocyanidin 3-O-glucoside, anthocyanidin 3,5-diglucoside are not suitable substrates for the 3GGT [Morita05].
Fujiwara98: Fujiwara H, Tanaka Y, Fukui Y, Ashikari T, Yamaguchi M, Kusumi T (1998). "Purification and characterization of anthocyanin 3-aromatic acyltransferase from Perilla frutescens." Plant Science, 137, 87-94.
Heller94: Heller W, Forkmann G (1994). "Biosynthesis of flavonoids." In: Harborne JB (editor) The flavonoids. Advances in research since 1986. Chapman & Hall, London Glasgow New York Tokyo Melbourne Madras, 499-537.
Kamsteeg78: Kamsteeg J, van Brederode J, van Nigtevecht G (1978). "Identification, properties, and genetic control of UDP-glucose: cyanidin-3-rhamnosyl-(1 leads to 6)-glucoside-5-O-glucosyltransferase isolated from petals of the red campion (Silene dioica)." Biochem Genet 16(11-12);1059-71. PMID: 751641
Kamsteeg80: Kamsteeg J, Van Brederode J, Van Nigtevecht G (1980). "Identification, properties and genetic control of UDP-L-rhamnose:anthocyanidin 3-O-glucoside, 6"-O-rhamnosyltransferase isolated from petals of the red campion (Silene dioica)." Z. Naturforsch., 35c, 249-257.
Morita05: Morita Y, Hoshino A, Kikuchi Y, Okuhara H, Ono E, Tanaka Y, Fukui Y, Saito N, Nitasaka E, Noguchi H, Iida S (2005). "Japanese morning glory dusky mutants displaying reddish-brown or purplish-gray flowers are deficient in a novel glycosylation enzyme for anthocyanin biosynthesis, UDP-glucose:anthocyanidin 3-O-glucoside-2''-O-glucosyltransferase, due to 4-bp insertions in the gene." Plant J 42(3);353-63. PMID: 15842621
Suzuki01a: Suzuki H, Nakayama T, Yonekura-Sakakibara K, Fukui Y, Nakamura N, Nakao M, Tanaka Y, Yamaguchi MA, Kusumi T, Nishino T (2001). "Malonyl-CoA:anthocyanin 5-O-glucoside-6"'-O-malonyltransferase from scarlet sage (Salvia splendens) flowers. Enzyme purification, gene cloning, expression, and characterization." J Biol Chem 276(52);49013-9. PMID: 11598135
Suzuki02a: Suzuki H, Nakayama T, Yonekura-Sakakibara K, Fukui Y, Nakamura N, Yamaguchi MA, Tanaka Y, Kusumi T, Nishino T (2002). "cDNA cloning, heterologous expressions, and functional characterization of malonyl-coenzyme a:anthocyanidin 3-o-glucoside-6"-o-malonyltransferase from dahlia flowers." Plant Physiol 130(4);2142-51. PMID: 12481098
Suzuki04a: Suzuki H, Sawada S, Watanabe K, Nagae S, Yamaguchi MA, Nakayama T, Nishino T (2004). "Identification and characterization of a novel anthocyanin malonyltransferase from scarlet sage (Salvia splendens) flowers: an enzyme that is phylogenetically separated from other anthocyanin acyltransferases." Plant J 38(6);994-1003. PMID: 15165190
Yamazaki02: Yamazaki M, Yamagishi E, Gong Z, Fukuchi-Mizutani M, Fukui Y, Tanaka Y, Kusumi T, Yamaguchi M, Saito K (2002). "Two flavonoid glucosyltransferases from Petunia hybrida: molecular cloning, biochemical properties and developmentally regulated expression." Plant Mol Biol 48(4);401-11. PMID: 11905966
Yamazaki99: Yamazaki M, Gong Z, Fukuchi-Mizutani M, Fukui Y, Tanaka Y, Kusumi T, Saito K (1999). "Molecular cloning and biochemical characterization of a novel anthocyanin 5-O-glucosyltransferase by mRNA differential display for plant forms regarding anthocyanin." J Biol Chem 274(11);7405-11. PMID: 10066805
YonekuraSakakib00: Yonekura-Sakakibara K, Tanaka Y, Fukuchi-Mizutani M, Fujiwara H, Fukui Y, Ashikari T, Murakami Y, Yamaguchi M, Kusumi T (2000). "Molecular and biochemical characterization of a novel hydroxycinnamoyl-CoA: anthocyanin 3-O-glucoside-6"-O-acyltransferase from Perilla frutescens." Plant Cell Physiol 41(4);495-502. PMID: 10845463
Kamsteeg78a: Kamsteeg J, Van Brederode J, Van Nigtevecht G (1978). "The formation of UDP-L-rhamnose from UDP-D-glucose by an enzyme preparation of red campion (Silene dioica (L) Clairv) leaves." FEBS Lett 91(2);281-4. PMID: 680134
Matsuba10: Matsuba Y, Sasaki N, Tera M, Okamura M, Abe Y, Okamoto E, Nakamura H, Funabashi H, Takatsu M, Saito M, Matsuoka H, Nagasawa K, Ozeki Y (2010). "A novel glucosylation reaction on anthocyanins catalyzed by acyl-glucose-dependent glucosyltransferase in the petals of carnation and delphinium." Plant Cell 22(10);3374-89. PMID: 20971893
Nakayama97: Nakayama M, Koshioka M, Shibata M, Hiradate S, Sugie H, Yamaguchi MA (1997). "Identification of cyanidin 3-O-(3",6"-O-dimalonyl-β-glucopyranoside) as a flower pigment of chrysanthemum (Dendranthema grandiflorum)." Biosci. Biotech. Biochem., 61(9), 1607-1608.
Rubio06: Rubio S, Larson TR, Gonzalez-Guzman M, Alejandro S, Graham IA, Serrano R, Rodriguez PL (2006). "An Arabidopsis mutant impaired in coenzyme A biosynthesis is sugar dependent for seedling establishment." Plant Physiol 140(3);830-43. PMID: 16415216
StPierre98: St-Pierre B, Laflamme P, Alarco AM, De Luca V (1998). "The terminal O-acetyltransferase involved in vindoline biosynthesis defines a new class of proteins responsible for coenzyme A-dependent acyl transfer." Plant J 14(6);703-13. PMID: 9681034
Suzuki03a: Suzuki H, Nakayama T, Nishino T (2003). "Proposed mechanism and functional amino acid residues of malonyl-CoA:anthocyanin 5-O-glucoside-6'''-O-malonyltransferase from flowers of Salvia splendens, a member of the versatile plant acyltransferase family." Biochemistry 42(6);1764-71. PMID: 12578391
Suzuki04b: Suzuki H, Nakayama T, Yamaguchi M, Nishino T (2004). "cDNA cloning and characterization of two Dendranthema × morifolium anthocyanin malonyltransferases with different functional activities." Plant Science 166:89-96.
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