Abstract
Human pro-urokinase cDNA was isolated from the cDNA library constructed from human kidney mRNA using the dC/dG homopolymer tailing method and Okayama-Berg method with pBR322 as a vector. A mature polypeptide starting with Ser was produced in Escherichia coli under the control of the tac promoter and the Shine-Dalgarno sequence of the catechol 2, 3-oxygenase gene derived from Pseudomonas putida. By replacing the sequence coding for N-terminal eight amino acids of pro-urokinase with the synthetic DNA oligomer, the bacterial pro-urokinase had a molecular weight of 47, 000 daltons and accounted for 15% of the insoluble fraction of E. coli proteins in induced cells. Its biological activity was restored by renaturing the bacterial product. The activity of bacterial pro-urokinase was 450 IU/ml culture.
