Flavone Glucosiduronic Acids

Polylysine has been shown to possess various biological activities. It is bacteriostatic (Katchalski, Bichowski-Slomnitzki & Volcani, 1953) and virostatic (Stahmann, Graf, Patterson, Walker & Watson, 1951); it inhibits thromboplastic activity (de Vries et al. 1951), fibrinolysis (Ginsburg, de Vries & Katchalski, 1952), the proteolytic activity of pepsin (Katchalski, Berger & Neumann, 1954) and the clearing action of heparin on alimentary lipemia (Stein, de Vries, Wislicki & Katchalski, 1954). In all the above-mentioned cases polylysine acts as a retarder ofbiological andenzymic processes. The effect reported here on the staphylocoagulase clotting reaction demonstrates that polylysine can also have an accelerating action in a specific biological system. This accelerating action of the basic peptide has been shown to affect the second stage of the staphylocoagulase clotting system, i.e. the clotting of fibrinogen by coagulase thrombin. In preliminary experiments it has also been observed that polylysine accelerates the clotting offibrinogen by thrombin. The mechanism of this acceleration is unknown. The following possibilities should be considered: (a) polylysine inactivates a coagulase thrombin inhibitor, (b) as a result of the interaction between polylysine and fibrinogen, a complex is formed which is attacked by the clotting agent more readily than fibrinogen itself, (c) the clotting time is shortened as the result of the ability of the highly charged threadlike polylysine molecules to form a link between the clotting agent and the fibrinogen; the local concentration of the clotting agent surrounding the fibrinogen molecules is thus increased and the clotting reaction enhanced. The fact that polylysine and protamine exert an accelerating activity on the staphylocoagulase clotting system, whereas polyaspartic acid shows no effect, suggests that this ability is associated with the polycationic nature of the effective peptides.