KEGG   ENZYME: 1.21.3.6Help
Entry
EC 1.21.3.6                 Enzyme                                 

Name
aureusidin synthase;
AmAS1
Class
Oxidoreductases;
Catalysing the reaction X-H + Y-H = X-Y;
With oxygen as acceptor
BRITE hierarchy
Sysname
2',4,4',6'-tetrahydroxychalcone 4'-O-beta-D-glucoside:oxygen oxidoreductase
Reaction(IUBMB)
(1) 2',4,4',6'-tetrahydroxychalcone 4'-O-beta-D-glucoside + O2 = aureusidin 6-O-beta-D-glucoside + H2O [RN:R08008];
(2) 2',3,4,4',6'-pentahydroxychalcone 4'-O-beta-D-glucoside + 1/2 O2 = aureusidin 6-O-beta-D-glucoside + H2O [RN:R08010];
(3) 2',3,4,4',6'-pentahydroxychalcone 4'-O-beta-D-glucoside + O2 = bracteatin 6-O-beta-D-glucoside + H2O [RN:R08009]
Reaction(KEGG)
Substrate
2',4,4',6'-tetrahydroxychalcone 4'-O-beta-D-glucoside [CPD:C16407];
O2 [CPD:C00007];
2',3,4,4',6'-pentahydroxychalcone 4'-O-beta-D-glucoside [CPD:C16408]
Product
aureusidin 6-O-beta-D-glucoside [CPD:C16409];
H2O [CPD:C00001];
bracteatin 6-O-beta-D-glucoside [CPD:C16410]
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-beta-D-glucoside in vivo [4].
History
EC 1.21.3.6 created 2003, modified 2012
Pathway
ec00941  Flavonoid biosynthesis
Orthology
K13079  aureusidin synthase
Reference
1  [PMID:11073455]
  Authors
Nakayama T, Yonekura-Sakakibara K, Sato T, Kikuchi S, Fukui Y, Fukuchi-Mizutani M, Ueda T, Nakao M, Tanaka Y, Kusumi T, Nishino T.
  Title
Aureusidin synthase: a polyphenol oxidase homolog responsible for flower coloration.
  Journal
Science 290:1163-6 (2000)
DOI:10.1126/science.290.5494.1163
  Sequence
Reference
2  [PMID:11418122]
  Authors
Nakayama T, Sato T, Fukui Y, Yonekura-Sakakibara K, Hayashi H, Tanaka Y, Kusumi T, Nishino T.
  Title
Specificity analysis and mechanism of aurone synthesis catalyzed by aureusidin synthase, a polyphenol oxidase homolog responsible for flower coloration.
  Journal
FEBS Lett 499:107-11 (2001)
DOI:10.1016/S0014-5793(01)02529-7
  Sequence
Reference
3  [PMID:11164594]
  Authors
Sato T, Nakayama T, Kikuchi S, Fukui Y, Yonekura-Sakakibara K, Ueda T, Nishino T, Tanaka Y, Kusumi T.
  Title
Enzymatic formation of aurones in the extracts of yellow snapdragon flowers.
  Journal
Plant Sci 160:229-236 (2001)
DOI:10.1016/S0168-9452(00)00385-X
Reference
4  [PMID:16832053]
  Authors
Ono E, Fukuchi-Mizutani M, Nakamura N, Fukui Y, Yonekura-Sakakibara K, Yamaguchi M, Nakayama T, Tanaka T, Kusumi T, Tanaka Y.
  Title
Yellow flowers generated by expression of the aurone biosynthetic pathway.
  Journal
Proc Natl Acad Sci U S A 103:11075-80 (2006)
DOI:10.1073/pnas.0604246103
  Sequence
Other DBs
ExplorEnz - The Enzyme Database: 1.21.3.6
IUBMB Enzyme Nomenclature: 1.21.3.6
ExPASy - ENZYME nomenclature database: 1.21.3.6
BRENDA, the Enzyme Database: 1.21.3.6
CAS: 320784-48-3

DBGET integrated database retrieval system