Purification of his-tagged UGT78K2 and determination of the reaction product and kinetics for cyanidin. (A) SDS-PAGE analysis of UGT78K2: total soluble protein from E. coli expressing UGT78K2 prior to induction with 100 lM IPTG (lane 1), 24 h post-induction (lane 2); IMAC-purified UGT78K2 (lane 3). (B) The UGT78K2 enzyme reaction as revealed by HPLC-DAD chromatograms at 520 nm (C). HPLC retention times: cyanidin (Rt: 10.1 min); cyanidin 3-O-glucoside (Rt: 7.1 min). (D) UGT78K2 kinetics for the cyanidin acceptor substrate using 5 mM UDPG as a sugar donor. Points represent the mean of three assays ± the standard deviation.