Stereoselective allosteric binding interaction on human serum albumin between ibuprofen and lorazepam acetate

The effect of ibuprofen enantiomers on the stereoselective binding of 3-acy loxy-1,4-benzodiazepines to human serum albumin (HSA) was studied using bot h native and Sepharose-immobilized protein. (S)-Lorazepam acetate exhibited considerably enhanced binding, especially in the presence of (+)-(S)-ibupr ofen. The phenomenon is an indication of cooperative allosteric interaction between different binding sites during multiple cobinding of two ligands. (C) 1999 Wiley-Liss, Inc.