The influence of molecular mass of sulfated propylene glycol ester of low-molecular-weight alginate on anticoagulant activities

Sulfated propylene glycol ester of low-molecular-weight alginate (PSS) was fractionated by low-pressure gel permeation chromatography. Four fractions (PSS1–4) with different weight-averaged molecular mass (51.95, 25.62, 11.76 and 5.41 kD, respectively) were obtained and their structural characteristics were determined and compared by Fourier transform infrared and nuclear magnetic resonance spectroscopes. Their anticoagulant activities were also studied by evaluating their influence on the activated partial thromboplastin time, thrombin time, anti-thrombin and anti-FXa factor activities mediated by anti-thrombin III and heparin cofactor II. The results demonstrated that PSS1–4 had similar structural parameters, such as the degree and pattern of sulfation and backbone, but their molecular masses were different. The bioassay results suggested that the anticoagulation was molecular mass dependent. PSS1 and PSS2 strongly inhibited the activity of thrombin mediated by heparin cofactor II and anti-thrombin III, whereas PSS4 only showed a very weak anti-thrombin activity. PSS1–3 weakly inhibited the activity of coagulation factor Xa mediated only by anti-thrombin III while PSS4 lacked the anti-Xa activity.