Unconcentrated human urinary proteins analysed by high resolution two‐dimensional electrophoresis with narrow pH gradients: Preliminary findings after occupational exposure to cadmium

Abstract Over 600 polypeptides were detected in the two‐dimensional patterns of unconcentrated human urine following ultrasensitive silver staining. Resolution was greatly improved using different carrier ampholyte (Ampholine) mixtures of narrow pH range during isoelectric focusing. The effects of freezing and thawing, dialysis, concentration and different protein denaturing procedures were investigated. Preliminary studies of the urinary protein patterns of workers occupationally exposed to cadmium for many years showed a pronounced but selective increase in the number and amounts of polypeptides of M r <40 000.