EC 2.4.1.360     
Accepted name: 2-hydroxyflavanone C-glucosyltransferase
Reaction: UDP-α-D-glucose + a 2′-hydroxy-β-oxodihydrochalcone = UDP + a 3′-(β-D-glucopyranosyl)-2′-hydroxy-β-oxodihydrochalcone
Glossary: 2′-hydroxy-β-oxodihydrochalcone = 1-(2-hydroxyphenyl)-3-phenypropan-1,3-dione
3′-(β-D-glucopyranosyl)-2′-hydroxy-β-oxodihydrochalcone = 1-(3-(β-D-glucopyranosyl)-2-hydroxyphenyl)-3-phenylpropan-1,3-dione
Other name(s): OsCGT
Systematic name: UDP-α-D-glucose:2′-hydroxy-β-oxodihydrochalcone C6/8-β-D-glucosyltransferase
Comments: The enzyme has been characterized in Oryza sativa (rice), various Citrus spp., Glycine max (soybean), and Fagopyrum esculentum (buckwheat). Flavanone substrates require a 2-hydroxy group. The meta-stable flavanone substrates such as 2-hydroxynaringenin exist in an equilibrium with open forms such as 1-(4-hydroxyphenyl)-3-(2,4,6-trihydroxyphenyl)propane-1,3-dione, which are the actual substrates for the glucosyl-transfer reaction (see EC 1.14.14.162, flavanone 2-hydroxylase). The enzyme can also act on dihydrochalcones. The enzymes from citrus plants can catalyse a second C-glycosylation reaction at position 5.
References:
1.  Brazier-Hicks, M., Evans, K.M., Gershater, M.C., Puschmann, H., Steel, P.G. and Edwards, R. The C-glycosylation of flavonoids in cereals. J. Biol. Chem. 284 (2009) 17926–17934. [PMID: 19411659]
2.  Nagatomo, Y., Usui, S., Ito, T., Kato, A., Shimosaka, M. and Taguchi, G. Purification, molecular cloning and functional characterization of flavonoid C-glucosyltransferases from Fagopyrum esculentum M. (buckwheat) cotyledon. Plant J. 80 (2014) 437–448. [PMID: 25142187]
3.  Hirade, Y., Kotoku, N., Terasaka, K., Saijo-Hamano, Y., Fukumoto, A. and Mizukami, H. Identification and functional analysis of 2-hydroxyflavanone C-glucosyltransferase in soybean (Glycine max). FEBS Lett. 589 (2015) 1778–1786. [PMID: 25979175]
4.  Ito, T., Fujimoto, S., Suito, F., Shimosaka, M. and Taguchi, G. C-Glycosyltransferases catalyzing the formation of di-C-glucosyl flavonoids in citrus plants. Plant J. 91 (2017) 187–198. [PMID: 28370711]
[EC 2.4.1.360 created 2018]