Stearoyl-Acyl Carrier Protein and Unusual Acyl-Acyl Carrier Protein Desaturase Activities Are Differentially Influenced by Ferredoxin1
AUTOR(ES)
Schultz, David J.
FONTE
American Society of Plant Physiologists
RESUMO
Acyl-acyl carrier protein (ACP) desaturases function to position a single double bond into an acyl-ACP substrate and are best represented by the ubiquitous Δ9 18:0-ACP desaturase. Several variant acyl-ACP desaturases have also been identified from species that produce unusual monoenoic fatty acids. All known acyl-ACP desaturase enzymes use ferredoxin as the electron-donating cofactor, and in almost all previous studies the photosynthetic form of ferredoxin rather than the non-photosynthetic form has been used to assess activity. We have examined the influence of different forms of ferredoxin on acyl-ACP desaturases. Using combinations of in vitro acyl-ACP desaturase assays and [14C]malonyl-coenzyme A labeling studies, we have determined that heterotrophic ferredoxin isoforms support up to 20-fold higher unusual acyl-ACP desaturase activity in coriander (Coriandrum sativum), Thunbergia alata, and garden geranium (Pelargonium × hortorum) when compared with photosynthetic ferredoxin isoforms. Heterotrophic ferredoxin also increases activity of the ubiquitous Δ9 18:0-ACP desaturase 1.5- to 3.0-fold in both seed and leaf extracts. These results suggest that ferredoxin isoforms may specifically interact with acyl-ACP desaturases to achieve optimal enzyme activity and that heterotrophic isoforms of ferredoxin may be the in vivo electron donor for this reaction.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=59173Documentos Relacionados
- Temporal and tissue-specific regulation of a Brassica napus stearoyl-acyl carrier protein desaturase gene.
- Stearoyl-acyl carrier protein delta 9 desaturase from Ricinus communis is a diiron-oxo protein.
- Modification of Brassica seed oil by antisense expression of a stearoyl-acyl carrier protein desaturase gene.
- Sequence of a cDNA from Linum usitatissimum encoding the stearoyl-acyl carrier protein desaturase.
- Nucleotide sequence of a stearoyl-acyl carrier protein desaturase cDNA from developing seeds of rice.
