Cyanohydrin beta-glucosyltransferase () is an enzyme that catalyzes the chemical reaction:
Tyrosine N-monooxygenase, the first enzyme in the pathway to dhurrin, converts L-tyrosine to (E)-(4-hydroxyphenyl)acetaldehyde oxime. Subsequently, (S)-4-hydroxymandelonitrile is formed by the action of 4-hydroxyphenylacetaldehyde oxime monooxygenase.
Cyanohydrin beta-glucosyltransferase uses uridine diphosphate glucose (UDP-D-glucose) to add the glucoside component. The enzyme is a glycosyltransferase, specifically one of the hexosyltransferases. The systematic name of this enzyme class is UDP-D-glucose:(S)-4-hydroxymandelonitrile beta-D-glucosyltransferase. Other names in common use include uridine diphosphoglucose-p-hydroxymandelonitrile, glucosyltransferase, UDP-glucose-p-hydroxymandelonitrile glucosyltransferase, uridine diphosphoglucose-cyanohydrin glucosyltransferase, uridine diphosphoglucose:aldehyde cyanohydrin, beta-glucosyltransferase, UDP-glucose:(S)-4-hydroxymandelonitrile beta-D-glucosyltransferase, UGT85B1, and UDP-glucose:p-hydroxymandelonitrile-O-glucosyltransferase.
The enzyme from Sorghum bicolor can act on a range of alcohols, not just the cyanohydrin group of 4-hydroxymandelonitrile.