title: The interaction of pteroylpolyglutamates with calf thymus thymidylate synthase.
abstract: Calf thymus thymidylate synthase was purified to homogeneity using a pteroyltetraglutamyllysine Sepharose affinity column. Inhibition of the purified enzyme by folate or methotrexate was enhanced by addition of gamma-Glu residues. Tetrahydrofolate, tetrahydropteroyltriglutamate and tetrahydropteroylheptaglutamate, all having the natural configuration at C-6, all showed similar Km values near 15 microM. Thus, although calf thymus thymidylate synthase showed a higher affinity for pteroylpolyglutamates than pteroylmonoglutamate, this was not reflected in lowered Km values with the corresponding tetrahydropteroylpolyglutamate substrates.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002846:Chromatography, Affinity; D005492:Folic Acid / Q000031:analogs & derivatives*; D007700:Kinetics; D008780:Methyltransferases / Q000378:metabolism*; D011485:Protein Binding; D011624:Pteroylpolyglutamic Acids / Q000378:metabolism / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D013940:Thymidylate Synthase / Q000378:metabolism*; D013950:Thymus Gland / Q000201:enzymology*
chemical_list: D011624:Pteroylpolyglutamic Acids; D005492:Folic Acid; D008780:Methyltransferases; D013940:Thymidylate Synthase