Fibrin binding, fibrinolytic and fibrinogenolytic activity of plasminogen activator derived from the paranasal mucous membrane of humans.

ABSTRACT

It is known that large amounts of plasminogen activator (PA) are contained in tissue extracts of the human paranasal mucous membrane (PMM) with chronic sinusitis. The present study was undertaken to isolate and purify the PA in tissue extracts of PMM. Furthermore, the purified PA was identified as to whether it was of the tissue type or urokinase (UK) type, and some of its fibrinolytic characteristics were determined in comparison with those of urokinase. As starting material, extracts of acetone powder of PMM with chronic sinusitis were used, and Zn-imminodiacetate affinity chromatography, and ultrafiltration were carried out to separate and purify the PA from the PMM. The PA was purified to a 107-fold increase in specific activity. The molecular weight of the PA was estimated to be 65,000 to 70,000 d by gel filtration using Sephacryl S-200. The purified PA was stable in the range of pH 8.0 to 9.0. Using S-2288, a synthetic substrate, the Michaelis constant (Km) of the purified PA was estimated to be 0.11 mmol. The binding of the purified PA to fibrin was stronger than that of UK, while the fibrinogenolytic activity of the purified PA was not stronger than that of UK. Based on these results, the purified PA was identified as a tissue-type plasminogen activator (t-PA). From the kinetic data, it was identified as being of the two-chain variety. It is considered that, as a thrombolytic agent, t-PA derived from the PMM could be more useful than UK.