The Protein Matter of Bile.*

The protein matter is undoubtedly one of the more important constituents of the bile, but in spite of this fact, only a relatively small amount of work seems to have been done upon it. The small amount of the substance in the fluid, combined with the extreme difficulty of purification, has delayed exact investigation. The early investigators, Fourcroy, Gmelin, Frommherz, Gugert, Simon, and Berzelius (l), each in turn, made a very superficial study of the properties of bile protein, without much attempt at its purification. Somewhat later, Landwehr (3) claimed that bile protein was a true mucin containing only nonreducing carbohydrates, because he found that boiling it with dilute acids failed to produce any substance which was capable of reducing alkaline copper sulfate. His “mucin” preparation upon analysis gave: C 53.09, H 7.6, 0 24.41, N 13.8, and S 1.1 per cent. Later he changed his views and stated that the protein which he analyzed was a mixture of globulin and glycocholic acid. Paijkull (2) showed that if we accept the analysis of Landwehr, the latter’s assumption of a mixture of globulin and glycocholic acid was practically an impossibility. Paijkull’s own work gave him a product with C 51.67, H 6.88, N 16.09, and S 1.74 per cent. He concluded that bile protein is not a true mucin, although it has some of the properties of a mucin;