THE STRUCTURE OF A COMPLEX BETWEEN CARBONIC-ANHYDRASE-II AND A NEW INHIBITOR, TRIFLUOROMETHANE SULFONAMIDE

It has recently been shown that aliphatic sulphonamides are good inhib itors of carbonic anhydrase (CA) provided that the pK of the sulphonam ide is low. We have determined the structure of the complex between CA II and CF3SO2NH2 by X-ray crystallographic methods. The nitrogen of th e sulphonamide is bound to the zinc ion of the enzyme in the usual man ner. The other parts of the inhibitor show a different mode of binding from aromatic sulphonamides since the trifluoromethyl group is bound at the hydrophobic part of the active site instead of pointing out fro m the active site. It should be possible to design new inhibitors spec ific for the different isoenzymes, starting from the present structure .