RESUMO
The stick insect, Anisomorpha buprestoides, and the catmint, Nepeta cataria, produce closely related cyclopentanoid terpenes, anisomorphal and nepetalactone. Tracer experiments with isotopes indicate that anisomorphal is synthesized by the walking stick from normal terpene precursors (acetate or mevalonate). In the catmint plant, isolated leaf disks synthesized nepetalactone, utilizing the same precursors.
Assuntos
Insetos/metabolismo , Plantas/metabolismo , Terpenos/biossíntese , Isótopos de Carbono , Cromatografia em Camada Fina , RadiometriaRESUMO
A cell-free system consisting of a soluble fraction and plastid fragments from pea shoots incorporates 2-(14)C-mevalonate very actively into farnesol, squalene, geranylgeraniol, and other isoprenoids of different carbon-chain lengths. The products have different cofactor requirements, which makes it possible to channel the pathway into different products by varying the incubation mixture.
Assuntos
Ácido Mevalônico/metabolismo , Plantas Comestíveis/metabolismo , Esqualeno/biossíntese , Terpenos/biossíntese , Isótopos de Carbono , Cromatografia em Camada Fina , Farneseno Álcool/biossíntese , Técnicas In Vitro , Lipídeos/análise , NAD , NADPRESUMO
It has been shown that a 10 000 x g matrix-free mitochondrial membrane-rich preparation from commercial bakers' yeast is able to synthesize 3-all-transhexaprenyl-4-hydroxybenzoate from 4-hydroxybenzoate and isopentenyl pyrophosphate. The synthesis is Mg2+ dependent and is stimulated markedly by the primer for polyprenylpyrophosphate synthesis of 3-hexaprenyl-4-hydroxybenzoate from 4-hydroxybenzoate, isopentenyl pyrophosphate and 3,3-dimethylallyl pyrophosphate the priming function of 3,3-dimethylallyl pyrophosphate can be performed by either geranyl pyrophosphate (most efficient) or farnesyl pyrophosphate. At high Mg2+ concentrations, however, geranyl pyrophosphate and farnesyl pyrophosphate act mainly as sources of preformed side chains and 3-diprenyl- and 3-tripenyl-4-hydroxybenzoate, respectively, are produced. In the presence of a source of preformed polyprenyl pyrophosphates the membrane preparations catalysed the polyprenylation of methyl-4-hydroxybenzoate, 4-hydroxybenzaldehyde, 4-hydroxybenzylalcohol and 4-hydroxycinnamate. No evidence was obtained for the involvement of either 4-hydroxybenzoyl CoA or 4-hydroxybenzoyl-S-protein in the formation of 3-polyprenyl-4-hydroxybenzoates.
Assuntos
Membranas Intracelulares/metabolismo , Mitocôndrias/metabolismo , Terpenos/biossíntese , Hidroxibenzoatos/biossíntese , Magnésio/farmacologia , Fosfatos de Poli-Isoprenil/farmacologia , Saccharomyces cerevisiae/metabolismoRESUMO
A membrane fraction isolated from the cellular slime mold Dictyostelium discoideum was incubated with GDP-[14C]mannose and found to catalyze the incorporation of [14C]mannose into an endogenous acceptor to yield a product with the chemical and chromatographic properties of a polyprenol phosphate sugar derivative. These results suggest that D. discoideum can synthesize a mannosyl phosphoryl polyprenol.
Assuntos
Dictyostelium/metabolismo , Hexosefosfatos/biossíntese , Mixomicetos/metabolismo , Terpenos/biossíntese , Guanosina Difosfato Manose/metabolismo , Manose/biossínteseRESUMO
The ability of adult B. pahangi and D. immitis to utilize [14C]-mevalonate for the biosynthesis of isoprenoid compounds was investigated. Both filariae appeared to be unable to synthesize squalene and sterols de novo. They did, however, synthesize ubiquinone 9, a family of dolichol isoprenologs, and predominantly, the short-chain isoprenoid alcohol, geranyl geraniol. In addition, B. pahangi and D. immitis apparently were unable to synthesize a menaquinone (Vitamin K2) from [14C]-menadione.