Proteins in the Colloidal Gold Reaction.

The colloidal gold test developed almost 35 years ago by Lange (1) has been utilized in studies of cerebrospinal pathology and of liver dysfunction with little more than a general understanding of the basic reasons for the production of the several reaction patterns. Rationalization of the mode of reaction by experimenting with blood protein fractions obtained by the usual salting out methods is difficult, if not impossible, because the fractions so obtained are mixtures (2) of proteins defined arbitrarily. A promising line of attack' upon the problem has been opened up by newer methods for the separation of the blood proteins (3, 4, 5), particularly those separable as electrophoretically homogeneous fractions. It has already been established (6, 7) that the gamma globulin fraction is responsible for the coagulation of the gold sol. The protective action postulated for the serum albumin, however, never has been demonstrated conclusively with concentrations likely to be encountered in body fluids. In investigating the use of the colloidal gold reaction for the detection of liver damage, the authors have used blood protein fractions prepared by the newer methods in an attempt to determine the relationships between relative concentrations of the protein fractions and the reaction curves obtained.