The side chain of arginine 176 within the bicarbonate binding site interacts significantly with the aromatic ring of the bithionol molecule.

This allosteric, conformational change interferes with the ability of the active site of soluble adenylyl cyclase to adequately bind ATP to convert it into cAMP.

[citation needed] In another form of inhibition, bithionol is a much larger molecule than simple sodium bicarbonate, so it is large enough to reach through a small channel in the soluble adenylyl cyclase and interfere with binding of ATP, preventing its conversion to cAMP.

[citation needed] However, concentrations of bithionol that are required inhibit soluble adenylyl cyclase at clinically relevant levels are also cytotoxic in vivo.

However, it sheds light on the search for a compound that will eventually be able to target the bicarbonate binding site of soluble adenylyl cyclase.