TABLE 3.

Kinetic constants of the H. neapolitanus carboxysomal carbonic anhydrase CsoSCA

FractionKinetic constant value for:
Hydration reactionaDehydration reactionb
kcat (s−1)Km (mM)kcat (s−1)Km (mM)
rCsoSCA(8.9 ± 0.5) × 1043.2 (± 0.4)(4.6 ± 1.2) × 1049.3 (± 2.1)
Broken carboxysomes(6.5 ± 0.9) × 1043.6 (± 0.7)(3.1 ± 0.8) × 10410.1 (± 3.2)
Intact carboxysomes(1.8 ± 0.2) × 10412.2 (± 2.3)NDND
  • a The hydration reaction was performed at pH 8.0.

  • b The dehydration reaction was performed at pH 7.0. ND, not determined.