Physicochemical characteristics of LR3-IGF1 protein inclusion bodies: Electrophoretic mobility studies

A knowledge of the physicochemical properties of inclusion bodies is import ant for the rational design of potential recovery processes such as flotati on and precipitation. In this study, measurement of the size and electropho retic mobility of protein inclusion bodies and cell debris was undertaken. SDS-PAGE analysis of protein inclusion bodies subjected to different cleani ng regimes suggested that electrophoretic mobility provides a qualitative m easure of protein inclusion body purity. Electrophoretic mobility as a func tion of electrolyte type and ionic strength was investigated. The presence of divalent ions produced a stronger effect on electrophoretic mobility com pared with monovalent ions. The isoelectric point of cell debris was signif icantly lower than that for the inclusion bodies. Hence, the contaminating cell debris may be separated from inclusion bodies using flotation by explo iting this difference in isoelectric points. Separation by this method is s imple, convenient, and a possible alternative to the conventional route of centrifugation.