TABLE 2.

Specific activities (nmol min−1 mg cell protein−1) of enzymes of the reductive and oxidative TCA cyclea

Enzyme activity testedSp act (nmol min−1 mg protein−1)
Thiomicrospira denitrificansCandidatus Arcobacter sulfidicus
Fumarate reductase220n.d.
Fumarate hydratase390n.d.
Isocitrate dehydrogenase1,1002,300
Malate dehydrogenase
    NADPH830810
    NADH960510
2-Oxoglutarate dehydrogenase
    NADP+<1<1
    NAD+<1<1
Pyruvate dehydrogenase
    NADP+<1<1
    NAD+<1<1
  • a Mean values were obtained from three independent experiments. Standard errors were less than ±20%. The assays were carried out at 25°C. n.d., not determined.