Saccharin Sulfonamides as Inhibitors of Carbonic Anhydrases I, II, VII, XII, and XIII

Table 1

Compound dissociation constants of human recombinant carbonic anhydrase isoforms I, II, VII, XII, and XIII, as determined by the fluorescent thermal shift assay (FTSA, 37°C, pH 7.0). Acetazolamide (AZM) was used as a control. Saccharin bound with the of 1 to over 10 mM while compound 4 reached the affinity of 0.3 to 25 nM.

Compound	Dissociation constants (nM) and CA isoforms
	CA I	CA II	CA VII	CA XII	CA XIII
1 (saccharin)	>10,000,000	2,900,000	1,000,000	5,900,000	2,000,000
2	3000	400	770	220	200
3	18	20	110	290	45
4	0.33	2.5	4.3	25	6.7
AZM	1400	38	17	130	50

Uncertainties of the FTSA measurements are approximately 1.6-fold in .