Large scale isolation of pig muscle phosphoglucose isomerase

A large-scale purification procedure for phosphoglucose isomerase from pig skeletal muscle is described. It consists of two fractionations by selective precipitation and two ion exchange chromatography steps yielding an end product of approximately 900 units (micromoles of substrate converted to product per min per mg of protein, at 30 degrees) specific activity. The method separates three isoenzymic forms with an overall recovery of about 30% of the original total enzyme activity in the form of Isoenzyme III, the latter being the predominant enzyme species.