The interaction of ligands with enzymes. A starting point in drug design

The problem of inhibiting a specific enzyme of a pathogen without inhibiting the corresponding enzyme of the host is one which has intrigued medicinal chemists for years. While it is easy to find potent inhibitors of purified enzymes transforming these inhibitors into effective drugs, it still is a very poorly understood business. This report discusses studies with two enzymes, papain and dihydrofolate reductase, and the nonspecific (phi and MR correlated) interaction of ligands with them. The QSAR which has been developed for the inhibition of dihydrofolate reductase by triazines is compared with the QSAR which has been reported for the same inhibitors acting against S. aureus.