PHYSIOCHEMICAL STUDIES OF FRACTIONATED BOVINE HEPARIN .3. SOME PHYSICAL PARAMETERS IN RELATION TO BIOLOGICAL ACTIVITY

Graded self-hydrolysis of commercial bovine heparin produced samples of varying anticoagulant activity. The hydrolysis results in desulfation, which is accompanied by decrease in sedimentation coefficient, intrinsic viscosity when measured in water, and axial ratios, a/b, if a prolate ellipsoid model is assumed. Intrinsic viscosities obtained in 0.5 M NaCl were relatively unchanged for the hydrolyzed samples. The drop in molecular weight during inactivation is due to desulfation and not to depolymerization. Hydrolysis results in both O- and N-desulfation, the latter to a greater extent than the former. The data suggest that degree of sulfation and size and/or shape confer on heparin its biological activity.