title: Models for the binding of methotrexate to Escherichia coli dihydrofolate reductase: direct effect of carboxylate of aspartic acid 27 upon ultraviolet spectrum of methotrexate.
mesh_terms: D001665:Binding Sites; D004926:Escherichia coli / Q000201:enzymology; D066298:In Vitro Techniques; D008727:Methotrexate / Q000378:metabolism*; D008956:Models, Chemical; D013056:Spectrophotometry, Ultraviolet; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism*
chemical_list: D013762:Tetrahydrofolate Dehydrogenase; D008727:Methotrexate