The most accurate method of determIning protem concentration is probably acid hydrolysis followed by amino acid analysis. Most other methods are sensitive to the amino acid composition of the protein and absolute concentrations cannot be obtained The procedure of
Lowry et al. (1) IS no exception, but its sensitivity is moderately constant from protein to protein, and It has been so widely used that Lowry protein estimations are a completely acceptable alternative to a ngorous absolute deter- mination In almost all CIrcumstances where protein mixtures or crude extracts are Involved.