Activity can be mEAsured with the thioredoxin-dependent reduction of insulin using recombinant rat thioredoxin reductase. The test mixture should contain 160 M insulin and 0.2 mM NADPH in 0.1 potassium phosphate, pH 7.0, containing 2 nM EDTA. In the presence of 10 M E. coli thioredoxin, 7 nM mammalian thioredoxin reductase will give an absorbance decrEAse of 0.034/min at 340 nm.[IMCO Catalog TRX-01-B]Technical InformationSynonymsTrx1Sourceone ampoule contains 2 mg thioredoxin from E. coliMW11.7 kDaFormulationLyophilized from 50 mM tris-HCl and 1 mM EDTA, pH 7.5