%0 Journal Article %A Stanley, S. H. %A Dalton, H. %T Role of Ribulose-1,5-bisphosphate Carboxylase/Oxygenase in Methylococcus capsulatus (Bath) %D 1982 %J Microbiology, %V 128 %N 12 %P 2927-2935 %@ 1465-2080 %R https://doi.org/10.1099/00221287-128-12-2927 %I Microbiology Society, %X Intact cells of the methane-oxidizing organism Methylococcus capsulatus (Bath) assimilated CO2 for several hours in the absence of methane, provided that an alternative energy source such as hydrogen and/or formate was available. Despite the presence of ribulose bisphosphate carboxylase and a ribulose monophosphate pathway in this organism, autotrophic growth in the presence of a suitable energy source could not be demonstrated. Radiolabelling studies suggested that the CO2 was incorporated via C3 carboxylation and ribulose bisphosphate carboxylase in the presence of both methane and hydrogen plus formate. However, in the presence of methane the CO2 was further metabolized into sugar phosphates, whereas in the absence of methane, but with hydrogen plus formate as an energy source, the sugar phosphates were not labelled to any significant extent. Of the methane-oxidizing bacteria tested, ribulose bisphosphate carboxylase was found only in M. capsulatus strains (Bath and Foster & Davis). The ribulose monophosphate pathway in M. capsulatus (Bath) probably uses the keto-deoxy-6-phosphogluconate route for the cleavage of fructose 6-phosphate into two C3 molecules rather than via phosphofructokinase and fructose bisphosphate aldolase which have low activities in this organism. The function of the ribulose bisphosphate carboxylase may be to provide an alternative cleavage pathway for the synthesis of 3-phosphoglycerate during growth on methane. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-128-12-2927