Improved two-dimensional gel electrophoresis representation of serum proteins by using ProtoClear.

ProtoClear is a proprietary technique for clearing albumin and immunoglobulin G (IgG) from human serum samples. Albumin constitutes 57-71% of total serum protein and IgG ranges from 8-26%. Removal of these two proteins alone clears approximately 75% of the total protein present in serum and allows the detection of the remaining proteins that are present in far lower concentrations. ProtoClear effectively removed >95% of human serum albumin (HSA) and >97% of human IgG as measured by an anti-HSA competitive immunoassay and a radial immunodiffusion assay, respectively. ProtoClear was far more specific at removing albumin and IgG than Cibracon Blue Dye chromatography (Cibracon Blue), the typically utilized alternative. Comparing two-dimensional (2-D) gels of serum cleared by either Cibracon Blue or by ProtoClear, it was apparent that Cibracon Blue removed a number of proteins in addition to albumin. Following removal of albumin and IgG from serum, we found a significant improvement in the resolution of polypeptide spots detected on two-dimensional gels.