TY - JOUR T1 - Inactivation by Mouse Serum of a Tightly Bound Inhibitor of Dihydrofolate Reductase JF - Molecular Pharmacology JO - Mol Pharmacol SP - 93 LP - 96 VL - 6 IS - 1 AU - ECKARD FĂ–LSCH AU - J. R. BERTINO Y1 - 1970/01/01 UR - http://molpharm.aspetjournals.org/content/6/1/93.abstract N2 - A potent inhibitor of dihydrofolate reductase, a substituted 4,6-diaminotriazine (NSC 113,423; a 1:1 compound of 4-[p-(4,6-diamino-2,2-dimethyl-s-triazine-1(2H)-yl)hydrocinnamido]-o-toluenesulfonyl fluoride and ethanesulfonic acid), was found to be rapidly inactivated by mouse serum. Preliminary studies on the mechanism of this inactivation indicate that a mouse serum protein hydrolyzes the sulfonyl fluoride group. However, this triazine inhibitor was not inactivated by the sera of other species, including rat, dog, and man. It is suggested that NSC 113,423 and related compounds may still be valuable chemotherapeutic agents against tumors occurring in man. ACKNOWLEDGMENTS NSC 113,423 and 117,664 were obtained from Dr. Florence White of the Cancer Chemotherapy Service Center, and from Dr. B. R. Baker, who also generously supplied the sulfonic acid derivative of NSC 117,664 as well as valuable advice. The expert technical assistance of Mrs. Inger-Anne Skjeltorp is also acknowledged. ER -