title: An isotopic assay for dihydrofolate reductase.
mesh_terms: D000818:Animals; D002606:Charcoal; D066298:In Vitro Techniques; D008099:Liver / Q000201:enzymology*; D008727:Methotrexate; D009249:NADP / Q000378:metabolism; D009573:Nitrites; D051381:Rats; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism*; D014316:Tritium
chemical_list: D009573:Nitrites; D014316:Tritium; D002606:Charcoal; D009249:NADP; D013762:Tetrahydrofolate Dehydrogenase; D008727:Methotrexate