Two reductases, P450 oxidoreductase and P450Bm-3 reductase, were purified on a 2 ' ,5 ' -adenosine diphosphate solid support. Although the efficiency of these columns is well established, the cost of the resin and the eluting material 2 ' -adenosine can be prohibitive. Herein we show that the less costly 2 ' ,3 ' -adenosine monophosphate is an excellent eluting material.