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 M potassium phosphate, pH 7.0, containing 2 mM EDTA. In the presence of 5 M human thioredoxin, 7 nM mammalian thioredoxin reductase will give an absorbance decrEAse of 0.10/min at 340 nm.[IMCO Catalog TRX-03 and TRX-03-B]Technical InformationSynonymsTrx1Sourceone ampoule contains recombinant human thioredoxin 1FormulationLyophilized from 163 l 50 mM tris-Cl, pH 7.5, 1 mM EDTAOriginAnimal/Rabbit