Effect of active oxygen species scavengers on fibrinolytic activity of some proteinases

Abstract

Scavengers of different active oxygen species affect fibrin plate lysis, catalysed by various proteinases, only at relatively high concentrations (>10 −2 M). Singlet oxygen scavengers change proteinase activity insignificantly except for strong inhibition of pepsin and papain by sodium azide, but pepsin - by histidine, and fibrinolytic urokinase activity - by all used 0 2 Δl scavengers. Of all used scavengers of ·OH-radical only ethanol caused significant changes in the proteinases under study, except for α-chymotrypsin. The most strong inhibitory effect on proteinase activity was demonstrated by scavengers of superoxide radical. Thus, nitrotetrazolium blue strongly inhibited the activity of plasmin, urokinase (fibrinolytic activity), papain and pepsin. Catalase changed proteinase activity insignificantly, though it leads to total inhibition of pepsin activity at final 4.5×10 −4 M concentration. These facts and our previous findings on generating of active oxygen species by proteinases give us grounds to suppose that minor active oxygen species, endogenous for the “proteinase-substrate” system, can participate in the catalytic function of some proteinases.