Table 1.

Kinetic parameters for the CO₂ hydration reaction catalyzed by the human cytosolic isozymes hCA I and II (α-class CAs) at 20 °C and pH 7.5 in 10 mM HEPES buffer and 20 mM Na₂SO₄, and the β-CA from M. tuberculosis (mtCA 1 and 2) and form E. histolytica EhiCA, measured at 20 °C, pH 8.3 in 20 mM TRIS buffer and 20 mM NaClO₄. Inhibition data with the clinically used sulfonamide acetazolamide (5-acetamido-1,3,4-thiadiazole-2-sulfonamide) are also provided [35].

Enzyme	Activity Level	Class	kcat	kcat/Km	KI (Acetazolamide)	Ref
			(s−1)	(M−1 s−1)	(nM)
hCA I	moderate	α	2.0 × 105	5.0 × 107	250	[12]
hCA II	very high	α	1.4 × 106	1.5 × 108	12	[12]
mtCA 1	moderate	β	3.9 × 105	3.7 × 107	480	[32]
mtCA 2	high	β	9.6 × 105	9.3 × 107	9.8	[32]
EhiCA	high	β	6.7 × 105	8.9 × 107	509	this work