Studies on the Mucoproteins of Human Plasma. I. Determination and Isolation 1

The presence in plasma of protein-like materials with properties of polypeptides or proteoses has been demonstrated repeatedly, but little has been done toward the characterization of these materials. The concentration of such materials in plasma rises markedly in patients with cancer or with cer- tain other diseases, but here again little is known of the source or significance of the increased levels. The relation of these protein-like materials to the glycoproteins and mucoproteins of plasma is like- wise in a state of considerable confusion.