Flavonol 3-O-glucosyltransferase

In enzymology, a flavonol 3-O-glucosyltransferase (EC 2.4.1.91) is an enzyme that catalyzes the chemical reaction

UDP-glucose + a flavonol UDP + a flavonol 3-O-beta-D-glucoside
Flavonol 3-O-glucosyltransferase
Flavonol 3-O-glucosyltransferase
Identifiers
EC no.2.4.1.91
CAS no.50812-18-5
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO
Search
PMCarticles
PubMedarticles
NCBIproteins

Thus, the two substrates of this enzyme are UDP-glucose and flavonol, whereas its two products are UDP and 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]

It is an enzyme found most notably in grapes (Vitis vinifera).[3] This enzyme is found within a number of other plants as well—such as snapdragons (Antirrhinum majus), kale (Brassica oleracea), and grapefruit (Citrus x paradisi).[4]

Pathways

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.[5] It is through this mechanism that the enzyme converts anthocyanidins to anthocyanins as a part of the phenylpropanoid pathway. One specific example would be this enzymes actions on pelargonidin. Flavonol 3-O-glucosyltransferase binds the glucoside to this protein, making pelargonidin 3-O-glucoside. This enzyme is also involved in the flavone glycoside pathway, and daphnetin modification in some organisms. The role of the enzyme in these pathways is, again, to bind a glucoside to the substrate to construct a flavonol 3-O-glucoside.[6]

The structure of pelargonidin.
The structure of pelargonidin 3-O-glucoside.

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).

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.[7]

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.[8] The primary active site residue of this enzyme is Asp181, as determined by studies of how mutations affect enzyme capacity.[9] There are several documentations of the crystalline structure of flavonol 3-O-glucosyltransferase (2C1X, 2C1Z, and 2C9Z),[10] and, based on these renderings of the enzyme, there is only one subunit in the quaternary structure of the molecule.

References

  1. http://brenda-enzymes.info/enzyme.php?ecno=2.4.1.91&Suchword=&reference=&organism%5B%5D=Vitis+vinifera&show_tm=0#REACTION TYPE
  2. Dooner, H.K. & Nelson, O.E. Biochem Genet (1977) 15: 509. doi:10.1007/BF00520194
  3. 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. doi:10.1016/S0168-9452(00)00425-8. PMID 11166442.
  4. "BRENDA - Information on EC 2.4.1.91 - flavonol 3-O-glucosyltransferase".
  5. http://brenda-enzymes.info/enzyme.php?ecno=2.4.1.91&Suchword=&reference=&organism%5B%5D=Vitis+vinifera&show_tm=0#SOURCE TISSUE
  6. "KEGG ENZYME: 2.4.1.115". www.genome.jp. Retrieved 2016-12-06.
  7. 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.
  8. 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.
  9. 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.
  10. 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.

Further reading

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