Two binding sites for ketoprofen exist in Bovine Serum Albumin resulti
ng in remarkably different circular dichroism and photoreactivity on t
he antiinflammatory drug, irrespective of its chirality. The slightly
different affinity of the ketoprofen antipodes for these sites allows
chiral recognition: the resultant photodiscrimination level is, howeve
r, too low for processes of photoresolution of practical interest. Ena
ntiomer affinity can be tuned by addition of foreign substances. A sim
ple model is able to account for the experimental results.