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EC 1.21.3.6 Details
show Brenda entryEC number
1.21.3.6
Accepted name
aureusidin synthase
Reaction
(1) 2′,4,4′,6′-tetrahydroxychalcone 4′-O-β-D-glucoside + O2 = aureusidin 6-O-β-D-glucoside + H2O;;(2) 2′,3,4,4′,6′-pentahydroxychalcone 4′-O-β-D-glucoside + ½ O2 = aureusidin 6-O-β-D-glucoside + H2O;;(3) 2′,3,4,4′,6′-pentahydroxychalcone 4′-O-β-D-glucoside + O2 = bracteatin 6-O-β-D-glucoside + H2O
Other name(s)
AmAS1
Systematic name
2′,4,4′,6′-tetrahydroxychalcone 4′-O-β-D-glucoside:oxygen oxidoreductase
CAS registry number
320784-48-3
Comment
A copper-containing glycoprotein that plays a key role in the yellow coloration of flowers such as Antirrhinum majus (snapdragon). The enzyme is a homologue of plant polyphenol oxidase [1] and catalyses two separate chemical transformations, i.e. 3-hydroxylation and oxidative cyclization (2′,-dehydrogenation). H2O2 activates reaction (1) but inhibits reaction (2). Originally considered to act on the phenol but now thought to act mainly on the 4′-O-β-D-glucoside in vivo [4].
History
created 2003, modified 2012
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1 Oxidoreductases
1.1.1 With NAD+ or NADP+ as acceptor
1.1.3.1 created 1961, deleted 1984 1.1.3.25 created 1986, deleted 2005 1.1.3.26 created 1989, deleted 2002 1.1.3.31 created 1992, deleted 2003 1.1.3.32 created 1999, deleted 2002 1.1.3.33 created 1999, deleted 2002 1.1.3.34 created 1999, deleted 2002 1.1.3.35 created 1999, deleted 2002 1.1.3.36 created 1999, deleted 2002 1.1.99.15 created 1978, deleted 1980 1.1.99.17 created 1982, deleted 2003
