In enzymology, an anthocyanin 3'-O-beta-glucosyltransferase is an enzyme that catalyzes the chemical reaction UDP-glucose + an anthocyanin ⇌ {\displaystyle \rightleftharpoons } UDP + an anthocyanin 3'-O-beta-D-glucosideThus, the two substrates of this enzyme are UDP-glucose and anthocyanin, whereas its two products are UDP and anthocyanin 3'-O-beta-D-glucoside. Wikipedia