(±)Amethopterin hydrate

Amethopterin is a folic acid antagonist and potent anticancer agent. Amethopterin blocks DNA synthesis by preventing the production of tetrahydrofolate cofactors which are required to make thymidine. Amethopterin is actively transported into cells by the folate transporter where it is converted to a high molecular weight polyglutamate metabolite by folylpolyglutamate synthase, a dihydrofolate reductase inhibitor.

Amethopterin is a folic acid antagonist and potent anticancer agent. Blocks DNA synthesis by blocking the production of tetrahydrofolate covactors required for the synthesis of thymidine. Amethopterin is actively transported into cells by the folate transporter. In the cell, it is converted to a high molecular weight polyglutamate metabolite by folylpolyglutamate synthase that, in turn, binds to dihydrofolate reductase and inhibits its activity. Amethopterin-polyglutamate is degraded intracellularly by γ-glutamyl hydrolase.

Add a minimal amount of 0.1 N NaOH to solubilize, then dilute in neutral buffer or saline. Diluted stock is stable for 1 week refrigerated and for 1 month frozen at −20 °C. References: Cell & Tissue Culture: Laboratory Procedures, Chapter 27, Page 27D:3.2 (A. Doyle, et al., eds, John Wiley) and Cell Biology: A Laboratory Handbook, vol. 2, page 417 (Julio E. Celis, ed., Academic Press).