2,4-diamino-5-(3,5-dimethoxy-4-substituted)-benzyl-pyrimidines as ligands in affinity chromatography of bacterial dihydrofolate reductases.

Inhibitors of the trimethoprim-type, bearing terminal amino, hydroxyl or carboxyl groups in position 4 of the benzene ring as well as methotrexate were coupled to either CH-Sepharose 4B, epoxy-activated Sepharose 6B or AH-Sepharose 4B, respectively. In contrast to the methotrexate-affinity gel, trimethoprim-like ligands retained bacterial but not mammalian dihydrofolate reductases. The affinity gels prepared with these ligands could be used for effective purification of bacterial dihydrofolate reductases (EC 1.5.1.3), but differed in their affinity for this enzyme.