Reaction: UDP-α-D-glucose + (S)-4-hydroxymandelonitrile = UDP + (S)-4-hydroxymandelonitrile β-D-glucoside
For diagram click here.
Glossary: dhurrin = (S)-4-hydroxymandelonitrile β-D-glucoside
Other name(s): uridine diphosphoglucose-p-hydroxymandelonitrile glucosyltransferase; UDP-glucose-p-hydroxymandelonitrile glucosyltransferase; uridine diphosphoglucose-cyanohydrin glucosyltransferase; uridine diphosphoglucose:aldehyde cyanohydrin β-glucosyltransferase; UDP-glucose:(S)-4-hydroxymandelonitrile β-D-glucosyltransferase; UGT85B1; UDP-glucose:p-hydroxymandelonitrile-O-glucosyltransferase; UDP-D-glucose:(S)-4-hydroxymandelonitrile β-D-glucosyltransferase
Systematic name: UDP-α-D-glucose:(S)-4-hydroxymandelonitrile β-D-glucosyltransferase (configuration-inverting)
Comments: Acts on a wide range of substrates in vitro, including cyanohydrins, terpenoids, phenolics, hexanol derivatives and plant hormones, in a regiospecific manner . This enzyme is involved in the biosynthesis of the cyanogenic glucoside dhurrin in sorghum, along with EC 22.214.171.124, tyrosine N-monooxygenase and EC 126.96.36.199, 4-hydroxyphenylacetaldehyde oxime monooxygenase. This reaction prevents the disocciation and release of toxic hydrogen cyanide .
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 55354-52-4
1. Reay, P.F. and Conn, E.E. The purification and properties of a uridine diphosphate glucose: aldehyde cyanohydrin β-glucosyltransferase from sorghum seedlings. J. Biol. Chem. 249 (1974) 5826-5830. [PMID: 4416442]
2. Jones, P.R., Møller, B.L. and Hoj, P.B. The UDP-glucose:p-hydroxymandelonitrile-O-glucosyltransferase that catalyzes the last step in synthesis of the cyanogenic glucoside dhurrin in Sorghum bicolor. Isolation, cloning, heterologous expression, and substrate specificity. J. Biol. Chem. 274 (1999) 35483-35491. [PMID: 10585420]
3. Hansen, K.S., Kristensen, C., Tattersall, D.B., Jones, P.R., Olsen, C.E., Bak, S. and Møller, B.L. The in vitro substrate regiospecificity of recombinant UGT85B1, the cyanohydrin glucosyltransferase from Sorghum bicolor. Phytochemistry 64 (2003) 143-151. [PMID: 12946413]
4. Busk, P.K. and Møller, B.L. Dhurrin synthesis in sorghum is regulated at the transcriptional level and induced by nitrogen fertilization in older plants. Plant Physiol. 129 (2002) 1222-1231. [PMID: 12114576]
5. Kristensen, C., Morant, M., Olsen, C.E., Ekstrøm, C.T., Galbraith, D.W., Møller, B.L. and Bak, S. Metabolic engineering of dhurrin in transgenic Arabidopsis plants with marginal inadvertent effects on the metabolome and transcriptome. Proc. Natl. Acad. Sci. USA 102 (2005) 1779-1784. [PMID: 15665094]