TABLE 3 

CO2 produced by various metabolic reactions and refixed by RuBisCOa

Substrate% of substrate converted to CO2 (relative to amt of substrate consumed)% of CO2 refixed by Calvin cycle (relative to amt of substrate converted to CO2)Net CO2 yield (% relative to amt of substrate consumed)
WTNifA*WTNifA*WTNifA*
Fumarateb40 ± 444 ± 421 ± 96 ± 132 ± 242 ± 2
Succinate37 ± 340 ± 249 ± 730 ± 519 ± 228 ± 2
Acetatec22 ± 223 ± 168 ± 1113 ± 36 ± 118 ± 1
Butyrate-HCO316 ± 115 ± 3180 ± 16e149 ± 36e−16 ± 1f−10 ± 3f
Butyrated23 ± 3 76 ± 176 ± 1
  • a Average values with 90% confidence intervals were derived from the fluxes shown in Fig. 1. Minor variations between CO2 yields in Tables 2 and 3 are due to changes made by the fitting algorithm to find the most likely set of fluxes to explain all of the data.

  • b  All values were calculated by grouping malate and fumarate as a single pool. This grouping results in different CO2 yields between Tables 2 and 3, because the CO2 yields in Table 2 were normalized to fumarate alone so that the amount of malate produced could also be reported. If fumarate and malate were grouped in Table 2, the CO2 yields would be the same as those reported in Table 3.

  • c  The acetate data were previously published (7).

  • d  Wild-type cells do not grow without the NaHCO3 supplement.

  • e  One hundred percent of the butyrate converted to CO2 was refixed along with CO2 from the NaHCO3 supplement.

  • f  The negative values indicate that there was a net uptake of CO2 from the NaHCO3.