Formation of benzoquinol moiety in cornoside by salidroside mono-oxygenase, a cytochrome P450 enzyme, from Abeliophyllum distichumcell suspension cultures.
Planta
; 216(3): 432-6, 2003 Jan.
Article
in En
| MEDLINE
| ID: mdl-12520334
ABSTRACT
A microsomal fraction prepared from Abeliophyllum distichumNakai (Oleaceae) cell suspension cultures oxidized salidroside, a glucoside of 4-hydroxyphenylethyl alcohol, to cornoside possessing a unique benzoquinol ring. The enzyme named salidroside mono-oxygenase required NADPH as the only cofactor, and molecular oxygen. The reaction was strongly inhibited by CO as well as several cytochrome P450 inhibitors, such as cytochrome c and miconazole, indicating the involvement of a cytochrome P450 enzyme. Salidroside mono-oxygenase accepted salidroside as the only substrate, but did not oxidize 4-hydroxyphenylethyl alcohol, the salidroside aglucone, and 4-hydroxybenzoic acid. The optimum pH of the reaction was 7.5, and apparent K(m) values for salidroside and NADPH were 44 micro M and 33 micro M, respectively. The benzoquinol ring formation mechanism is discussed in comparison to the mechanism for ipso substitution of 4-hydroxybenzoate by active oxygen species followed by elimination leading to hydroquinone.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Phenols
/
Cyclohexanones
/
Oleaceae
/
Cytochrome P-450 Enzyme System
/
Glucosides
/
Mixed Function Oxygenases
Language:
En
Journal:
Planta
Year:
2003
Document type:
Article
Affiliation country:
Japan