Transformation of glutamate to delta-aminolevulinic acid by soluble extracts of Chlorobium vibrioforme.
AUTOR(ES)
Rieble, S
RESUMO
Formation of the tetrapyrrole pigment precursor delta-aminolevulinic acid (ALA) from glutamate was detected and partially characterized in extracts of the strictly anaerobic green photosynthetic bacterial species Chlorobium vibrioforme by using assay methods derived from those developed for algae and cyanobacteria. ALA formation in Chlorobium extracts was saturated at 10 mM glutamate and required NADPH and ATP at optimal concentrations of 0.3 and 3 mM, respectively. Preincubation of the enzyme extract with RNase A destroyed the ALA-forming activity completely. Activity in the RNase-treated extract was restored by supplementation with Chlorobium RNA after addition of RNasin to block further RNase action. RNA from the cyanobacterium Synechocystis sp. strain PCC 6803 and Escherichia coli tRNAGlu also restored activity. Activity was inhibited 50% by 0.2 microM hemin. ALA formation was completely abolished by the addition of 5 microM 3-amino-2,3-dihydrobenzoic acid (gabaculine). These results indicate that Chlorobium extracts share with those of plants, eucaryotic algae, cyanobacteria, prochlorophytes, and methanogens the capacity for RNA-dependent ALA formation from glutamate.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=210125Documentos Relacionados
- Intermolecular nitrogen transfer in the enzymic conversion of glutamate to delta-aminolevulinic acid by extracts of Chlorella vulgaris.
- delta-Aminolevulinic acid synthase from Euglena gracilis.
- Biosynthesis of delta-aminolevulinic acid by blue-green algae (cyanobacteria).
- Control of hemoglobin synthesis in the cultured chick blastoderm by delta-aminolevulinic acid synthetase: increase in the rate of hemoglobin formation with delta-aminolevulinic acid.
- Delta-aminolevulinic acid-requiring mutant from Escherichia coli.
