Flavonol 3-O-glucosyltransferase
| Flavonol 3-O-glucosyltransferase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 | |||||||||
| Identifiers | |||||||||
| EC no. | 2.4.1.91 | ||||||||
| CAS no. | 50812-18-5 | ||||||||
| Databases | |||||||||
| BRENDA | enzyme data | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | enzyme entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| Rhea | reactions | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
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Flavonol 3-O-glucosyltransferase (EC 2.4.1.91) is an enzyme that catalyzes the general chemical reaction
- UDP-glucose + a flavonol UDP + a flavonol 3-O-beta-D-glucoside
The two substrates of this enzyme are UDP-glucose and a flavonol. Its products are uridine diphosphate (UDP) and the corresponding flavonol 3-O-beta-D-glucoside. The flavonoids that can act as substrates within this reaction include quercetin, kaempferol, dihydrokaempferol, kaempferid, fisetin, and isorhamnetin. Flavonol 3-O-glucosyltransferase is a hexosyl group transfer enzyme.[1]
This enzyme is known by the systematic name UPD-glucose:flavonol 3-O-D glucosyltransferase, and it participates in flavonoid biosynthesis and causes the formation of anthocyanins. Anthocyanins produce a purple color in the plant tissues that they are present in.[2]
Occurrence
Flavonol 3-O-glucosyltransferase is found in grapes (Vitis vinifera),[3] parsley,[4] snapdragons (Antirrhinum majus), kale (Brassica oleracea), tulip bulbs,[5] peony,[6] and grapefruit (Citrus x paradisi).[7]
Function
This enzyme is involved in the biosynthesis of secondary metabolites. The primary function of this enzyme within its pathway is binding a glucoside onto a flavonol molecule, forming a flavonol 3-O-glucoside. For example, it converts quercetin to isoquercetin:[1]
A glucose unit is transferred from UDP-glucose to a specific hydroxy group of the flavonol, with uridine diphosphate (UDP) as a byproduct. By the same mechanism, the enzyme converts anthocyanidins to anthocyanins as a part of the phenylpropanoid pathway. For example, pelargonidin is transformed into callistephin (pelargonidin 3-O-glucoside).
This enzyme is also involved in the flavone glycoside pathway, and daphnetin modification in some organisms.[8]
Nomenclature
This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is UDP-glucose:flavonol 3-O-D-glucosyltransferase. Other names in common use include:
- GTI,
- uridine diphosphoglucose-flavonol 3-O-glucosyltransferase,
- UDP-glucose:flavonol 3-O-glucosyltransferase, and
- UDP-glucose:flavonoid 3-O-glucosyltransferase (UFGT).[8]
Among those, UFGT is divided into UDP-glucose: Flavonoid 3-O-glucosyltransferase (UF3GT) and UDP-glucose: Flavonoid 5-O-glucosyltransferase (UF5GT), which are responsible for the glucosylation of anthocyanins to produce stable molecules.[6]
Inhibitors and structure of the enzyme
Some of the inhibitors of this enzyme include CaCl2, CoCl2, Cu+2, CuCl2, KCl, Mg+2, and Mn+2.[9] The primary active site residue of this enzyme is Asp181, as determined by studies of how mutations affect enzyme capacity.[10] There are several documentations of the crystalline structure of flavonol 3-O-glucosyltransferase (2C1X, 2C1Z, and 2C9Z),[11] and, based on these renderings of the enzyme, there is only one subunit in the quaternary structure of the molecule.
References
- 1 2 Kleinehollenhorst, G.; Behrens, H.; Pegels, G.; Srunk, N.; Wiermann, R. (1982). "Formation of Flavonol 3-O-Diglycosides and Flavonol 3-O-Triglycosides by Enzyme Extracts from Anthers of Tulipa cv. Apeldoorn / Characterization and Activity of Three Different O -Glycosyltransferases during Anther Development". Zeitschrift für Naturforschung C. 37 (7–8): 587–599. doi:10.1515/znc-1982-7-808.
- ↑ Dooner, H. K.; Nelson, O. E. (1977). "Genetic control of UDPglucose:flavonol 3-O-glucosyltransferase in the endosperm of maize". Biochemical Genetics. 15 (5–6): 509–519. doi:10.1007/BF00520194. PMID 880210.
- ↑ Kobayashi S, Ishimaru M, Ding CK, Yakushiji H, Goto N (February 2001). "Comparison of UDP-glucose:flavonoid 3-O-glucosyltransferase (UFGT) gene sequences between white grapes (Vitis vinifera) and their sports with red skin". Plant Sci. 160 (3): 543–550. Bibcode:2001PlnSc.160..543K. doi:10.1016/S0168-9452(00)00425-8. PMID 11166442.
- ↑ Sutter A, Grisebach H (1973). "UDP-glucose: flavonol 3-0-glucosyltransferase from cell suspension cultures of parsley". Biochim. Biophys. Acta. 309 (2): 289–95. doi:10.1016/0005-2744(73)90027-2. PMID 4731963.
- ↑ Wiermann R (1982). "Formation of flavonol 3-O-diglycosides and flavonol 3-O-triglycosides by enzyme extracts from anthers of Tulipa cv apeldoorn - characterization and activity of 3 different O-glycosyltransferases during anther development". Z. Naturforsch. C. 37: 587–599. doi:10.1515/znc-1982-7-808. S2CID 37241803.
- 1 2 Zhao DQ, Han CX, Ge JT, Tao J (November 2012). "Isolation of a UDP-glucose: Flavonoid 5-O-glucosyltransferase gene and expression analysis of anthocyanin biosynthetic genes in herbaceous peony (Paeonia lactiflora Pall.)". Electronic Journal of Biotechnology. 15 (6). doi:10.2225/vol15-issue6-fulltext-7.
- ↑ "BRENDA - Information on EC 2.4.1.91 - flavonol 3-O-glucosyltransferase".
- 1 2 Enzyme 2.4.1.91 at KEGG Pathway Database.
- ↑ Schomburg, Professor Dietmar; Schomburg, Dr Ida, eds. (1 January 2006). "Flavonol 3-O-glucosyltransferase". Springer Handbook of Enzymes. Vol. 32. Springer Berlin Heidelberg. pp. 21–29. doi:10.1007/978-3-540-49534-5_2. ISBN 978-3-540-32591-8.
- ↑ Hiromoto, Takeshi; Honjo, Eijiro; Noda, Naonobu; Tamada, Taro; Kazuma, Kohei; Suzuki, Masahiko; Blaber, Michael; Kuroki, Ryota (2016-12-06). "Structural basis for acceptor-substrate recognition of UDP-glucose: anthocyanidin 3-O-glucosyltransferase from Clitoria ternatea". Protein Science. 24 (3): 395–407. doi:10.1002/pro.2630. ISSN 0961-8368. PMC 4353365. PMID 25556637.
- ↑ Offen, W; Martinez-Fleites, C; Yang, M; Kiat-Lim, E; Davis, B.G; Tarling, C.A; Ford, C.M; Bowles, D.J; Davies, G.J. (2006-01-01). "Structure of a Flavonoid Glucosyltransferase Reveals the Basis for Plant Natural Product Modification". EMBO J. 25 (6): 1396–405. doi:10.1038/sj.emboj.7600970. PMC 1422153. PMID 16482224.