Ultrathin‐layer sodium dodecyl sulfate‐polyacrylamide gradient gel electrophoresis and silver staining of urinary proteins

Abstract

Abstract Ultrathin‐layer sodium dodecyl sulfate‐polyacrylamide gradient gel electrophoresis in combination with silver staining is a highly sensitive and rapid method for molecular size analysis of urinary proteins. First results are achieved after 4 h (electrophoretic run, 100 min, followed by Coomassie Brilliant Blue staining, 2 h). After additional silver staining, including a recycling step, the results are ready for evaluation within 7 h. Urine samples do not need to be concentrated. Within a single gel, 25–27 samples can be run side by side under identical conditions and thus compared without ambiguity. By coelectrophoresis of pure proteins and immunological analysis 13 urinary proteins could be identified and for 7 of them the detection limits were determined. Glomerular protein patterns in samples of urine with a protein concentration in the normal range are compared with the concentration of albumin and transferrin measured by a sensitive enzyme immunoassay. Typical renal and extrarenal protein patterns are shown.