title: Depression of the synthesis of the intermediate and large forms of ribulose-1,5-bisphosphate carboxylase/oxygenase in Rhodopseudomonas capsulata.
abstract: Rhodopseudomonas capsulata produces both an intermediate (I) and a large (L) form of ribulose-1,5-bisphosphate carboxylase/oxygenase. Both forms are derepressed under CO2-limiting conditions. The L-form of the enzyme is completely repressed when the culture is grown either photoautotrophically or photoheterotrophically with malate as the electron donor. The L-form is derepressed in the late logarithmic phase of growth when cells are grown photoheterotrophically with butyrate as the electron donor and the NaHCO3 supplement is 0.01%. The level of the I-form is increased about fivefold under latter growth conditions when compared to malate-grown cells. Analytical ultracentrifugation revealed the molecular masses of the I- and L-forms to be 300,000 and 542,000, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed the I-form to be composed of only one type subunit with a molecular weight of 64,000. The L-form possessed both large and small subunits with molecular weights of 58,000 and 10,000.
mesh_terms: D001639:Bicarbonates / Q000494:pharmacology; D002087:Butyrates / Q000494:pharmacology; D020148:Butyric Acid; D002245:Carbon Dioxide / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004794:Enzyme Repression / Q000187:drug effects; D008970:Molecular Weight; D012241:Rhodopseudomonas / Q000187:drug effects / Q000201:enzymology*; D012273:Ribulose-Bisphosphate Carboxylase / Q000096:biosynthesis*; D017693:Sodium Bicarbonate
chemical_list: D001639:Bicarbonates; D002087:Butyrates; D020148:Butyric Acid; D002245:Carbon Dioxide; D017693:Sodium Bicarbonate; D012273:Ribulose-Bisphosphate Carboxylase