Rhea - reaction knowledgebase

Enzymes

UniProtKB ^help_outline	1 proteins
Enzyme class ^help_outline	EC 2.4.1.234 kaempferol 3-O-galactosyltransferase
GO Molecular Function ^help_outline	GO:0033834 kaempferol 3-O-galactosyltransferase activity

Reaction participants Show >> << Hide

Name ^help_outline kaempferol Identifier CHEBI:58573 Charge -1 Formula C15H9O6 InChIKey^help_outline IYRMWMYZSQPJKC-UHFFFAOYSA-M SMILES^help_outline Oc1ccc(cc1)-c1oc2cc(O)cc(O)c2c(=O)c1[O-] 2D coordinates Mol file for the small molecule Search links Involved in 10 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Name ^help_outline UDP-α-D-galactose Identifier CHEBI:66914 Charge -2 Formula C15H22N2O17P2 InChIKey^help_outline HSCJRCZFDFQWRP-ABVWGUQPSA-L SMILES^help_outline OC[C@H]1O[C@H](OP([O-])(=O)OP([O-])(=O)OC[C@H]2O[C@H]([C@H](O)[C@@H]2O)n2ccc(=O)[nH]c2=O)[C@H](O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 105 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Name ^help_outline H⁺ Identifier CHEBI:15378 Charge 1 Formula H InChIKey^help_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILES^help_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,431 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Name ^help_outline kaempferol 3-O-β-D-galactoside Identifier CHEBI:76104 Charge -1 Formula C21H19O11 InChIKey^help_outline JPUKWEQWGBDDQB-DTGCRPNFSA-M SMILES^help_outline OC[C@H]1O[C@@H](Oc2c(oc3cc([O-])cc(O)c3c2=O)-c2ccc(O)cc2)[C@H](O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 1 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Name ^help_outline UDP Identifier CHEBI:58223 Charge -3 Formula C9H11N2O12P2 InChIKey^help_outline XCCTYIAWTASOJW-XVFCMESISA-K SMILES^help_outline O[C@@H]1[C@@H](COP([O-])(=O)OP([O-])([O-])=O)O[C@H]([C@@H]1O)n1ccc(=O)[nH]c1=O 2D coordinates Mol file for the small molecule Search links Involved in 576 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule

Cross-references

	RHEA:15709	RHEA:15710	RHEA:15711	RHEA:15712
Reaction direction	undefined	left-to-right	right-to-left	bidirectional
UniProtKB ^help_outline	1 proteins
EC numbers ^help_outline	2.4.1.234
Gene Ontology ^help_outline	GO:0033834
KEGG ^help_outline				R06808
MetaCyc ^help_outline				2.4.1.234-RXN

Publications

Purification, cloning, and heterologous expression of a catalytically efficient flavonol 3-O-galactosyltransferase expressed in the male gametophyte of Petunia hybrida.

Miller K.D., Guyon V., Evans J.N.S., Shuttleworth W.A., Taylor L.P.

Flavonols are plant-specific molecules that are required for pollen germination in maize and petunia. They exist in planta as both the aglycone and glycosyl conjugates. We identified a flavonol 3-O-galactosyltransferase (F3GalTase) that is expressed exclusively in the male gametophyte and controls ... >> More

Flavonols are plant-specific molecules that are required for pollen germination in maize and petunia. They exist in planta as both the aglycone and glycosyl conjugates. We identified a flavonol 3-O-galactosyltransferase (F3GalTase) that is expressed exclusively in the male gametophyte and controls the formation of a pollen-specific class of glycosylated flavonols. Thus an essential step to understanding flavonol-induced germination is the characterization of F3GalTase. Amino acid sequences of three peptide fragments of F3GalTase purified from petunia pollen were used to isolate a full-length cDNA clone. RNA gel blot analysis and enzyme assays confirmed that F3GalTase expression is restricted to pollen. Heterologous expression of the F3GalTase cDNA in Escherichia coli yielded active recombinant enzyme (rF3GalTase) which had the identical substrate specificity as the native enzyme. Unlike the relatively nonspecific substrate usage of flavonoid glycosyltransferases from sporophytic tissues, F3GalTase uses only UDP-galactose and flavonols to catalyze the formation of flavonol 3-O-galactosides. Kinetic analysis showed that the k(cat)/K(m) values of rF3GalTase, using kaempferol and quercetin as substrates, approaches that of a catalytically perfect enzyme. rF3GalTase catalyzes the reverse reaction, generation of flavonols from UDP and flavonol 3-O-galactosides, almost as efficiently as the forward reaction. The biochemical characteristics of F3GalTase are discussed in the context of a role in flavonol-induced pollen germination. << Less

J. Biol. Chem. 274:34011-34019(1999) [PubMed] [EuropePMC]

Comments

Published in: "Partial purification and some properties of flavonol 3-O-glycosyltransferases from seedlings of Vigna mungo, with special reference to the formation of kaempferol 3-O-galactoside and 3-O-glucoside" Ishikura, N.; Mato, M.; Plant Cell Physiol. 34, 329-335 (1993)