[Analysis of the secondary structure of urokinase by the circular dichroism method].

The secondary structure of urokinase with molecular weight 33 000 dalton was studied by the circular dichroism method. The secondary structure parameters were calculated based on the protein reference CD spectra resulted in the following secondary structure parameters: approximately 30% aminoacid residues constitute the alpha-helical regions, the same amount forms the beta-structure and an essential fractions contributes the beta-turns. Conformational stability of urokinase to alkaline pH (up to 11.6) and high temperature (up to 80 degrees) in 0.1 M phosphate buffer pH 6.6 was found.