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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
1.1.1.70 created 1965, deleted 1978 1.1.1.74 created 1972, deleted 1976 1.1.1.89 created 1972, deleted 1976 1.1.1.109 created 1972, deleted 1976 1.1.1.139 created 1972, deleted 1978 1.1.1.155 created 1976, deleted 2004 1.1.1.171 created 1978, deleted 1984 1.1.1.180 created 1983, deleted 1984 1.1.1.182 created 1983, deleted 1990 1.1.1.204 created 1972 as EC 1.2.1.37, transferred 1984 to EC 1.1.1.204, modified 1989, deleted 2004 1.1.1.242 created 1992, deleted 2001 1.1.1.253 created 1999, deleted 2003
1.1.2 With a cytochrome as acceptor 1.1.99.15 created 1978, deleted 1980 1.1.99.17 created 1982, deleted 2003
