In order to identify urinary proteins excreted from normal subjects, we employed a new method by which molecular weight and immunochemical property of urinary proteins can be determined simultaneously. Urine was subjected to linear gradient (3∼40%) SDS-PAGE and then transferred to nitrocellulose membrane by electrophoretic blotting method. The membrane was stained with Auro Dye and blotted proteins were identified by enzyme immunoassay using specific antibodies. In this method, we identified more than 12 protein bands from urine, that is, α2-macroglobulin, tubular epithelial antigen, Tamm-Horsfall glycoprotein, IgA, IgG, transferrin, albumin, α1-microglobulin, L-chain (dimer, monomer), retinol-binding protein, and β2-microglobulin. In addition, we found native forms and some fragments of immunoglobulins. In this report, we analyzed only normal subjects.
These results suggest that this method is useful for analysis not only of glomerular or tubular proteins but also tissue antigens from urine with various kinds of renal diseases.
