TABLE 1.

Specific activities (nmol min−1 mg cell protein−1) of key enzymes of autotrophic CO2 fixation pathwaysa

Enzyme activity testedSp act (nmol min−1 mg protein−1)
Thiomicrospira denitrificansCandidatus Arcobacter sulfidicusControl
Calvin cycle
    RubisCO<1<1100 (R. eutropha)
Reductive acetyl-CoA pathway
    CO dehydrogenase (MV)<2<1900 (D. autotrophicum)
    Pyruvate:acceptor (BV) oxidoreductase340170560 (D. autotrophicum)
3-Hydroxypropionate cycle
    Malonyl-CoA reductase<1<1160 (C. aurantiacus)
    Propionyl-CoA synthase<1<1100 (C. aurantiacus)
Reductive citric acid cycle
    ATP citrate lyase6545900 (D. hydrogenophilus)
    2-Oxoglutarate:acceptor (BV) oxidoreductase360175510 (D. hydrogenophilus)
    Pyruvate:acceptor (BV) oxidoreductase340170330 (D. hydrogenophilus)
  • a Mean values were obtained from three independent experiments. Standard errors were less than ±20%. The assays were carried out at 25°C.