Iridoid biosynthesis in staphylinid rove beetles (Coleoptera: Staphylinidae, Philonthinae).
Insect Biochem Mol Biol
; 31(6-7): 583-91, 2001 Apr 27.
Article
em En
| MEDLINE
| ID: mdl-11267897
ABSTRACT
The biosynthesis of chrysomelidial and plagiodial was studied in the rove beetle subtribe Philonthina (Staphylinidae). Glandular homogenates were found to convert synthetic (2E,6E)-[trideuteromethyl-5,5-(2)H(5)]octa-2,6-diene-1,8-diol (10) into nor-chrysomelidial (14) and nor-plagiodial (13). The overall transformation requires; i) oxidation of the substrate at C(1) and C(8), ii) cyclization of the resulting dialdehyde to nor-plagiodial followed by iii) isomerization to give nor-chrysomelidial. The oxidase requires molecular oxygen as a cofactor and operates with removal of the pro-R hydrogen from C(1) and C(8) of synthetic (1R,8R,2E,6E)-[1,8-(2)H(2)]-2,6-dimethyl-octa-2,6-diene-1,8-diol (15), producing a dialdehyde along with H(2)O(2). Unlike enzymes from iridoid-producing leaf beetle larvae, the Philonthus enzyme is able to oxidize saturated substrates such as citronellol. Crude protein extracts prepared from Philonthus glands by ammonium sulfate precipitation, were found to produce hydrogen peroxide at a rate of 0.085+/-0.003 ng H(2)O(2) (ng protein)(-1) hr(-1) with nerol as an oxidase substrate. The cyclase operates with opposite stereochemistry to the enzyme(s) from Phaedon cochleariae and other herbivorous leaf beetles, specifically removing the C(5)-H(R) hydrogen atom from (4R,5S,2E,6E)-[4,5-(2)H(2)]-2-methyl-octa-2,6-diene-1,8-diol (17). These findings have enabled us to construct a detailed account of iridoid biosynthesis in rove beetles, which resembles the biosynthetic route in leaf beetle larvae, but exhibits distinct stereochemical differences.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Piridinas
/
Terpenos
/
Besouros
/
Monoterpenos
Limite:
Animals
Idioma:
En
Revista:
Insect Biochem Mol Biol
Assunto da revista:
BIOLOGIA MOLECULAR
/
BIOQUIMICA
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Estados Unidos