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October 11, 1947

Current Comment

JAMA. 1947;135(6):356. doi:10.1001/jama.1947.02890060036012

FRACTIONATION OF SERUM PROTEIN  The electrophoretic method of protein fractionation appears to have become the standard of comparison for the older methods based on precipitation with neutral salts. Serum proteins are separated on the basis of their rate of movement in an electric field, into the principal fractions, albumin and alpha, beta and gamma globulin; the albumin is the fastest moving compound, the gamma globulin the slowest moving. The fractionation obtained by precipitation with salt appears to be sensitive to the exact salt concentration employed; by choice of appropriate concentrations the albumin is made to correspond approximately with the electrophoretically determined albumin, the pseudoglobulin to the alpha and beta globulin and the euglobulin to the gamma globulin.1 Thus it appears that salt fractionation may be used to give a fair approximation of the values obtained with the technically difficult electrophoretic method. The quantitative interpretation of electrophoretic data in terms of