Purification and Characterization of Recombinant Urokinase from Escherichia coli

Recombinant urokinase has been refolded and purified from Escherichia coli in both its high and low molecular weight forms. The low molecular weight form of the protein has been characterized by specific activity, amino acid composition, amino terminal analysis, carboxy terminal analysis, tryptic mapping, antibody titrations, and chromatographic behavior. The high molecular weight form has been characterized by specific activity and chromatographic behavior. With the exception of the lack of carbohydrate attached to Asn 302, the recombinant urokinase is almost identical to natural urokinase in every way tested. The results indicate that the urokinase can be properly folded from E. coli and that the carbohydrate attached to natural urokinase does not play a role in the catalytic activity of the enzyme.