Molecular Pharmacology, Vol 3, 279-283, Copyright © 1967 by the American Society for Pharmacology and Experimental Therapeutics

Comparison of Folate Reductases of Sarcoma 180 Cells, Sensitive and Resistant to Amethopterin

¹ Department of Experimental Therapeutics, Roswell Park Memorial Institute, Buffalo, New York 14203

Folate reductases of sublines of mouse Sarcoma 180 cells grown in vitro, sensitive and resistant (AT/3000) to amethopterin were compared. For this purpose the pattern of gel filtration on Sephadex G-75, the electrophoretic mobility on cellulose acetate strips, and the ratio of specific activities when folate or dihydrofolate were used as substrates were determined. No differences between these enzymes were noted. This, together with previous studies, leads to the conclusion that the only change which occurred when these cells became resistant to amethopterin by 3000-fold was a 300-fold increase in the cellular content of folate reductase.

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ACKNOWLEDGMENTS This investigation was supported in part by a research grant CA-04175 from the National Cancer Institute of the United States Public Health Service.