Quantifying Recombinant Proteins and Their Degradation Products Using SDS-PAGE and Scanning Laser Densitometry

Abstract

Numerous methods are widely used for the quantitation of proteins and their degradation products. Gel electrophoresis, followed by scanning laser densitometry, offers an accurate, sensitive, and reproducible technique that can be used at any stage during the production and purification of recombinant proteins. This technique offers many advantages over others for two main reasons: (1) proteolytic degradation is common among these proteins, and this method is able to accurately quantify degradation in both minute and large amounts; and (2) the common constituents of fermentation broths, refolding tanks, and purification processes do not interfere with the analysis. Analyses of a recombinant malarial protein at two different stages of purity will be used as examples to illustrate this method.