Comparative Studies With the Photooxidase of Rhodospirillum

Ibanez, M. L.; Lindstrom, E. S.

doi:10.1139/m61-010

Cited by 2 publications

(3 citation statements)

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“…Chromatophores from Rhodospirillumn rubrumii (Esmarch) Molisch strain Si were isolated from alumina-ground extracts of cells grown on lactateyeast extract, as has been previously detailed (Ibanez and Lindstrom, 1961a). These preparations sedimented as a homogeneous peak in a Spinco Model E analytical centrifuge with an uncorrected sedimentation rate of 160S, and contained particles predominately of 1,000 A diameter when examined in an electron microscope.…”

Section: Methodsmentioning

confidence: 99%

“…Protein in the extracts was measured by a modified biuret reaction (Ibanez and Lindstrom, 1961a). Nucleotides were obtained from the Pabst Laboratories and 2,6-dichlorophenol indophenol from General Biochemicals, Inc. Succinate-2-C'4 was obtained from Volk Radiochemica] Co. Table 1 indicate that PAPS can be synthesized from sulfate and ADP only in the light.…”

Section: Methodsmentioning

confidence: 99%

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METABOLISM OF SULFATE BY THE CHROMATOPHORE OF RHODOSPIRILLUM

Ibanez

Lindstrom

1962

J Bacteriol

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The chromatophore of Rhodospirillum rubrum was shown to possess enzymes for the activation and reduction of inorganic sulfate. The chromatophore was able to synthesize 3'-phosphoadenosine 5'-phosphosulfate (PAPS), using either exogenous adenosine triphosphate (ATP) or ATP synthesized via photophosphorylation. Light was required for the reduction of sulfate to a volatile form, presumably sulfite. Light enhanced the incorporation of sulfate-sulfur into cystine, cysteine, and cysteic acid of the chromatophore. This incorporation was probably the result of exchange reactions of reduced sulfur, not the result of net synthesis. The 100:1 ratio of the activation to reduction of sulfate and the inhibition of the reduction by exogenous ATP suggested that PAPS might not be the substrate for chromatophoral sulfate reduction. The bacterial chromatophore has been shown to mediate not only a number of photochemical reactions but also several dark reactions (Frenkel, 1959b). Two of the more physiologically significant photochemical reactions are the lightinduced esterification of phosphate (Frenkel, 1956) and the light-induced reduction of pyridine nucleotide (Frenkel, 1959a). Rhodospirillum rubrum is able to satisfy its sulfur requirement by assimilating inorganic sulfate either in the light or dark. As R. rubrum has been shown to reduce sulfate photochemically (Ibanez and Lindstrom, 1959), we wished to determine the relationship between the chromatophoral photometabolism

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

METABOLISM OF SULFATE BY THE CHROMATOPHORE OF RHODOSPIRILLUM

Ibanez

Lindstrom

1962

J Bacteriol

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show abstract

“…

Mild heat has been shown to destroy two absorption bands characteristic of the spectrum of bacteriochlorophyll in the chromatophore of R. rubrum (3,8) while the photooxidase assay is relatively heat insensitive (10,18). By comparing the effect of mild heat treatments on both the spectrum and on the photoxidase activity of the chromatophore, a validation was sought of the photooxidase assay using reduced indophenol.

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confidence: 99%