Clot lysis: role of plasminogen activator inhibitors in haemostasis and therapy.

An unimpeded circulation of blood depends on the concerted activation of coagulation and fibrinolytic factors. The latter entails the controlled, localised conversion of plasma zymogen plasminogen to the active enzyme plasmin mediated by tissue-type plasminogen activator (tPA). Bulk of tPA activity is in the proximity of the endogenous plasminogen activator inhibitor (PAI) as an active complex.

A molecular variant of plasminogen activator inhibitor of rat decidual tissue.

Artificially induced rat decidual tissue expresses plasminogen activator inhibitor (PAI). This PAI, isolated and purified employing chromatographic techniques, is a low molecular weight protein unlike the known PAIs. The final purified preparation resolves into a single band following SDS-PAGE and has an approximate molecular weight of 29 kDa.

Characterization of urokinase-type plasminogen activator of rat decidual tissue.

Urokinase-type plasminogen activator (uPA) from artificially induced decidual tissue of rat has been purified to homogeneity employing chromatographic techniques and the final preparation has a specific activity of 12,084 I.U./mg.

Enhanced expression of urokinase-type plasminogen activator in the rat endometrium following induction of decidualisation.

Urokinase-type plasminogen activator(uPA) assayed in uteri of cycling and deciduoma bearing rats shows detectable levels of this enzyme in endometrium. Zymographic analysis confirms uPA of decidual tissue and, following artificial induction of decidualisation, uPA activity constantly increases in the decidualising endometrium reaching a peak on day 9 of pseudopregnancy. Endometrial uPA of nonpregnant rats does not show any significant change during estrous cycle.

Isolation and purification of plasminogen activator from Yoshida ascites Sarcoma of rats.

The plasminogen activator was purified to the extent of 150-fold from 20,000 x g supernatant of Yoshida ascites Sarcoma by ammonium sulphate precipitation at 33% saturation followed by affinity chromatography on p-aminobenzamidine-Sepharose 4B. The specific activity of the purified activator was 10,260 IU/mg expressed in terms of International units of urokinase, the known activator of plasminogen. The activator was homogeneous by polyacrylamide slab gel electrophoresis with an apparent molecular weight 75 kDa by gel filtration on Sephadex G-100.

Protein kinases from liver mitochondria of tumour-bearing rats.

The mitochondria of liver of Yoshida ascites tumour-bearing rats contained two forms of protein kinase distinguishable on the basis of their kinetic properties, substrate specificity and responses to cyclic adenosine 3',5'-monophosphate (cAMP). One of these (kinase I) was activated 2-3 fold by cAMP while the other form (kinase II) was insensitive to the action of cAMP. Kinase I which was selective towards histone F1 as substrate was obtained as a homogeneous preparation and was observed to have a molecular weight of 170 000 by Sephadex G-150 gel filtration.

Histone kinase and cell division.

1. The activity of the soluble phosphokinase for histone F1 increases in regenerating rat liver during the first period of DNA synthesis after partial hepatectomy. The increase probably represents new enzyme synthesis.