Summary
The saliva of the tsetse, Glossina morsitans morsitans Westwood, has antithrombin anticoagulant activity and inhibits thrombin’s esterolytic
activity. It has no other detectable anticoagulant properties. The anticoagulant elutes
in a single peak on Sephadex fraction, is immediately acting, heat and storage stable,
and has a molecular weight of 11-13,000. Unlike heparin it is not neutralized by protamine
sulphate or toluidine blue and does not require the co-factor, antithrombin III, for
optimal anticoagulant activity. It has similar properties to hirudin, but does not
elute with a protein peak upon Sephadex fractionation and has a slightly different
molecular weight. Salivary gland homogenates contained neither a plasminogen activator
nor fibrinolytic activity. The sera of rabbits used to maintain tsetses, which contained
precipitating antibodies against saliva, did not neutralize the salivary anticoagulant
in vitro. The properties of this anticoagulant suggest that it might be a potentially useful
antithrombotic agent in man.
