Photosynthesis in Rhodospirillum rubrum
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چکیده
Ribulose 1,5-diphosphate carboxylase has been isolated from autotrophically cultured Rhoclospirillum rubrum. The molecular weight is 120,000. The K, for ribulose 1,5diphosphate is 83 mM, and for CO2 is 59 mM. The enzyme is inhibited by three important metabolites: citrate, an intermediate of the tricarboxylic acid cycle; inorganic phosphate; and 3-phosphoglyceric acid, the product of the reaction catalyzed by the carboxylase. Both the levels and the activity of ribulose 1,5-diphosphate carboxylase are apparently subject to metabolic control in this facultative photoautotroph.
منابع مشابه
Rhodospirillum rubrum possesses a variant of the bchP gene, encoding geranylgeranyl-bacteriopheophytin reductase.
The bchP gene product of Rhodobacter sphaeroides is responsible for the reduction of the isoprenoid moiety of bacteriochlorophyll (Bchl) from geranylgeraniol (GG) to phytol; here, we show that this enzyme also catalyzes the reduction of the isoprenoid moiety of bacteriopheophytin (Bphe). In contrast, we demonstrate that a newly identified homolog of this gene in Rhodospirillum rubrum encodes an...
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متن کاملPhotosynthesis in Rhodospirillum rubrum
Ribulose 1,5-diphosphate carboxylase has been isolated from autotrophically cultured Rhoclospirillum rubrum. The molecular weight is 120,000. The K, for ribulose 1,5diphosphate is 83 mM, and for CO2 is 59 mM. The enzyme is inhibited by three important metabolites: citrate, an intermediate of the tricarboxylic acid cycle; inorganic phosphate; and 3-phosphoglyceric acid, the product of the reacti...
متن کاملPhotosynthesis in Rhodospirillum rubrum. 3. Metabolic control of reductive pentose phosphate and tricarboxylic acid cycle enzymes.
Enzymes of the reductive pentose phosphate cycle including ribulose-diphosphate carboxylase, ribulose-5-phosphate kinase, ribose-5-phosphate isomerase, aldolase, glyceraldehyde-3-phosphate dehydrogenase and alkaline fructose-1,6-diphos-phatase were shown to be present in autotrophically grown Rhodospirillum rubrum. Enzyme levels were measured in this organism grown photo- and dark heterotrophic...
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