Influence of detergents on the measurement of the fibrinolytic activity of plasminogen activators.

The influence of detergents on the apparent activity of tissue plasminogen activator and of urokinase was investigated. The nonionic detergents Tween 80 and Triton X-100 and the zwitterionic detergent Zwittergent 314 caused a marked increase in the apparent activity of tissue plasminogen activator and, to a lesser degree, of urokinase in the fibrin plate assay, particularly at higher activator concentrations. The detergents did not enhance the plasma clot lysis in the presence of urokinase or tissue plasminogen activator. The anionic detergent sodium dodecyl sulfate had a small inhibitory action on the fibrin plate activity of urokinase and strongly inhibited the fibrin plate activity of tissue plasminogen activator. A systematic study into the mechanism of the stimulatory action of nonionic and zwitterionic detergents is presented.