Flavonol 3-O-Glucosyltransferase

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Short description: Class of enzymes
Flavonol 3-O-glucosyltransferase
Identifiers
EC number2.4.1.91
CAS number50812-18-5
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO

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]

Occurence

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]

  1. REDIRECT Template:Chemical reaction

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).

  1. REDIRECT Template:Chemical reaction

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. ↑ 1.0 1.1 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. 
  2. ↑ 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. 
  3. ↑ "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. February 2001. doi:10.1016/S0168-9452(00)00425-8. PMID 11166442. Bibcode: 2001PlnSc.160..543K. 
  4. ↑ "UDP-glucose: flavonol 3-0-glucosyltransferase from cell suspension cultures of parsley". Biochim. Biophys. Acta 309 (2): 289–95. 1973. doi:10.1016/0005-2744(73)90027-2. PMID 4731963. 
  5. ↑ 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. 
  6. ↑ 6.0 6.1 "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). November 2012. doi:10.2225/vol15-issue6-fulltext-7. 
  7. ↑ "BRENDA - Information on EC 2.4.1.91 - flavonol 3-O-glucosyltransferase". https://www.brenda-enzymes.org/enzyme.php?ecno=2.4.1.91. 
  8. ↑ 8.0 8.1 Enzyme 2.4.1.91 at KEGG Pathway Database.
  9. ↑ "Flavonol 3-O-glucosyltransferase". Springer Handbook of Enzymes. 32. Springer Berlin Heidelberg. 1 January 2006. pp. 21–29. doi:10.1007/978-3-540-49534-5_2. ISBN 978-3-540-32591-8. 
  10. ↑ 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. PMID 25556637. 
  11. ↑ Offen, W; Martinez-Fleites, C; Yang, M; Kiat-Lim, E; Davis, B.G; Tarling, C.A; Ford, C.M; Bowles, D.J et al. (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. PMID 16482224. PMC 1422153. https://www.rcsb.org/pdb/explore.do?structureId=2c1z. 



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Categories: [EC 2.4.1] [Enzymes of known structure] [Flavonols metabolism]

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