Determination of the Intracellular Concentration of Inorganic Pyrophosphate in Rhodospirillum rubrum
Rhodospirillum rubrum is a purple, non-sulphur phototrophic bacterium. This organism is capable of catalyzing the synthesis of inorganic pyrophosphate (PPi) upon illumination. The phosphorylation of Pi to PPi is catalyzed by the membrane bound proton translocating inorganic pyrophosphatase (the H+-PPase) (1). PPi is also formed during the biosynthesis of cellular constituents such as proteins and nucleic acids. Beside the H+-PPase there is also a soluble PPase in R. rubrum (soluble PPases are found in all types of cells). The soluble enzyme only catalyze the hydrolysis of PPi not the synthesis, When PPi is hydrolyzed by the soluble PPase, the energy liberated upon hydrolysis of the anhydride bond is lost.
KeywordsIntracellular Concentration Soluble Enzyme Proton Motive Force Cellular Constituent Phototrophic Bacterium
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- 1.Nyrén, P. (1985) Doctoral thesis, Univ. of Stockholm, Stockholm, Sweden.Google Scholar