Table 1.

Measured and literature data for the binding of carbonic anhydrase to seven sulfonamides.

Entry	Ligand Kd	Kdobs (nM)a	Kd or Ki (nM)b
1	trifluoromethane sulfonamide	14	2 – 13
2	4-nitrobenzene sulfonamide	95	65
3	4-methylbenzene sulfonamide	290	84
4	4-carboxybenzene sulfonamide	440	270
5	cyanidec	1,200	2,600
6	4-aminobenzene sulfonamide	18,000	3,000 – 23,000
7	methane sulfonamide	69,000	70,000 – 320,000

^aCalculated by fitting plots of levitation height versus time (Figure 3) to our RD model (Figure 1).

^bLiterature values; see reference 4 and references therein.

^cSodium counterion.