title: Two different species of dihydrofolate reductase in mammalian cells differentially resistant to amethopterin and methasquin.
mesh_terms: D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D004351:Drug Resistance; D005493:Folic Acid Antagonists / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000378:metabolism; D007700:Kinetics; D008727:Methotrexate / Q000494:pharmacology*; D008970:Molecular Weight; D009153:Mutagens; D009249:NADP / Q000378:metabolism; D011799:Quinazolines / Q000494:pharmacology*; D013762:Tetrahydrofolate Dehydrogenase / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D005493:Folic Acid Antagonists; D007527:Isoenzymes; D009153:Mutagens; D011799:Quinazolines; D009249:NADP; D013762:Tetrahydrofolate Dehydrogenase; D008727:Methotrexate