Identification of Rat Urinary Proteins by Zone and Immunoelectrophoresis. ∗

Summary

Separation and identification of male rat urinary proteins have been accomplished by zone electrophoresis on paper, in dilute agar and starch-gel media and by immunoelectrophoresis. Approximately 15 individual proteins have been delineated of which 7 are derived from serum while the remainder appear to be unique to the urine. The serum proteins are albumin, α₁ of Darcy, α₁-S3.5 glycoprotein, haptoglobin, “pi” protein, transferrin and γ globulin. Those associated only with urine are 2 prealbumins, a protein migrating as does albumin, an α₁ globulin, 2 α₂, 1 β, and a γ globulin. One of the α₂ globulins, α_2u, is quantitatively the major component of the urinary proteins and appears to be glycoprotein in nature.

ADDENDUM. After preparation and submission of this manuscript, a report by Bao-Linh et al(20) appeared describing the existence of 5 proteins unique to rat urine. The major urinary component was also shown to be an α₂ globulin.