A modification of the Lowry procedure to simplify protein determination in membrane and lipoprotein samples

The original Lowry method of protein determination has been modified by the addition of sodium dodecyl sulfate in the alkali reagent and an increase in the amount of copper tartrate reagent. These alterations allowed the method to be used with membrane and lipoprotein preparations without prior solubilization or lipid extraction and with samples containing 200 mm sucrose or 2.5 mm EDTA.