Table 2.

Kinetic parameters for the CO₂ hydration reaction catalysed by the human isozymes hCA I, II, III, IV, VA, VB, VI, VII, IX, XII, XIII, and XIV (α-class CAs) and the β-CAs from Leishmania donovani chagasi (LdcCA), Drosophila melanogaster (DmBCA), Anopheles gambiae (AgaCA) and Ascaris lumbricoides (AlBCA)

Enzyme	Class	kcat (s−1)	kcat/Km (M−1x s−1)	Ki (acetazolamide) (nM)a
hCA I	α	2.0×105	5.0×107	250 ± 12
hCA II	α	1.4×106	1.5×108	12 ± 0.8
hCA III	α	1.3×104	2.5×105	240000 ± 25000
hCA IV	α	1.1×106	5.1×107	74 ± 5.5
hCA VA	α	2.9×105	2.9×107	63 ± 2.1
hCA VB	α	9.5×105	9.8×107	54 ± 3.0
hCA VI	α	3.4×105	4.9×107	11 ± 0.7
hCA VII	α	9.5×105	8.3×107	2.5 ± 0.11
hCA IX	α	1.1×106	1.5×108	16 ± 0.8
hCA XII	α	4.2×105	3.5×107	5.7 ± 0.04
hCA XIII	α	1.5×105	1.1×107	16 ± 0.3
hCA XIV	α	3.1×105	3.9×107	41 ± 2.2
LdcCA	β	9.35×105	5.9 ×107	91.7 ± 5.7
DmBCA	β	9.5×105	1.1×108	516 ± 24
AgaCA	β	7.2×105	5.6×107	27.3 ± 2.0
AlBCAa	β	(6.0 ± 0.1) ×105	(4.3 ± 0.2) ×107	84.1 ± 2.9

^aMean ± standard error from three different assays