Macromolecular Heparin from Rat Skin

Abstract

Abstract Heparin with a molecular weight of 1.1 x 106 and sedimentation coefficient of 12.8 S has been isolated from Pronase-digested rat skin. The limiting viscosity number of this product is 16 times that of a commercial preparation from pig intestinal mucosa. The high molecular weight range of this polydisperse material was confirmed by gel filtration on columns of agarose gel. No depolymerization was observed on such columns in the presence of 6 m guanidinium hydrochloride, 8 m urea, or 4 m NaCl. Oxidative-reductive depolymerization with ascorbate gave two fractions on gel filtration media and two components on electrophoresis in agarose gel. Further study of these components led to the concept of a higher molecular weight polysaccharide core fraction to which chains of heparin in the same molecular weight range as commercial heparins were bound by ascorbate-sensitive linkages. Analyses for amino acids and xylose showed that the xylosylserine linkage-to-protein region was concentrated within the polysaccharide core fraction. A core preparation which represented only 8% of the weight of the undegraded macromolecule contained 42% of the total serine. These results show that macromolecular heparin from rat skin has a highly branched structure.