RAPID, RADIOCHEMICAL-LIGAND BINDING ASSAY FOR METHOTREXATE

摘要

A radiochemical ligand binding assay for methotrexate is provided. A binder factor comprising a partially purified dihydrofolic acid reductase preparation is employed. The binder factor is conveniently prepared by homogenizing a factor containing animal organ such as liver, and extracting with isotonic saline and ammonium sulfate. A binder cofactor, NADPH2, is also employed in the binding reaction. The procedure contemplates both direct and sequential assay techniques, and it is not interfered with by vast excesses of many natural folate derivatives.