aureusidin synthase activity https://github.com/geneontology/go-ontology/issues/28070 2',4,4',6'-tetrahydroxychalcone:oxygen oxidoreductase activity MetaCyc:RXN-8008 MetaCyc:RXN-3102 RHEA:34199 GO:0033793 molecular_function RHEA:34203 RHEA:34195 Catalysis of the reactions: 2',4,4',6'-tetrahydroxychalcone 4'-O-beta-D-glucoside + H+ + O2 = aureusidin 6-O-beta-glucoside + H2O, 2 2',3,4,4',6'-pentahydroxychalcone 4'-O-beta-D-glucoside + 2 H+ + O2 = 2 aureusidin 6-O-beta-glucoside + 2 H2O, and 2',3,4,4',6'-pentahydroxychalcone 4'-O-beta-D-glucoside + H+ + O2 = bracteatin 6-O-beta-glucoside + H2O. This activity consists of two separate chemical transformations: 3-hydroxylation and oxidative cyclization (2',-dehydrogenation). EC:1.21.3.6 MetaCyc:RXN-6242 MetaCyc:RXN-8456 oxidoreductase activity, acting on X-H and Y-H to form an X-Y bond, with oxygen as acceptor