Analysis of proteinuria by electrophoresis I. Sodium dodecyl sulfate polyacrylamide gel electrophoresis

Abstract

In order to find whether the electrophoretic patternes of urine proteins had any rela-tion to clinical and histopathological classifications of various renal diseases, sodium dodecyl sulfate polyacrylamide 4-30% gradient gel electrophoresis (SDS-PAGE) was carried out using SDS and 2-mercaptoethanol on the urine of 6 healthy subjects and 100 patients. Urine proteins were classified into five zones according to their molecular weight (MW). They were high MW (HMW), middle MW (MMW), moderately low MW (MLMW), low MW (LMW) and very low MW (VLMW). A nearly equal distribution from HMW to LMW was found in normal subjects and in minimal change of chronic glomerulonephritis. Predominant MMW was found in minimal change nephrotic patients. Though the histological findings revealed minimal change, the appearance of LMW and VLMW as well as MMW suggested the possibility of focal glomerulosclerosis. A wide range of excretion from HMW to VLMW, especially high density of VLMW was found in chronic renal failure and crescentic glomerulonephritis with normal serum creatinine level. Characteristic patterns were also found in renal tubular acidosis and multiple myeloma. It was found that the SDS-PAGE patterns of urine proteins had a good correlation with clinical and histopathological classifications in some renal diseases.