Determination of protein in adipose tissue extracts

An accurate and sensitive method for determination of protein in adipose tissue extracts based on a scaled-down version of the method of Lowry et al. (1951, J. Biol. Chem. 193, 265–275) is described. Protein is quantitatively precipitated by trichloroacetic acid with a nonionic detergent as a bulk-increasing substance and the precipitate is extracted with an organic solvent. This interference caused by lipids, sulfhydryl reagents, and several other compounds is eliminated. The accuracy of the determination of dilute reference protein solutions (2–20 µg/ml) is demonstrated.