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1991
Conference Paper
Title
Preparation of defined Heparin fragments by enzymatic fragmentation of Heparin.
Other Title
Herstellung definierter Heparin-Fragmente durch enzymatische Spaltung von Heparin
Abstract
Heparin is a linear, water-soluble glycosaminoglycan containing numerous negatively charged groups. It is widely used in the internal and post-operative medicine as an antithrombotic drug to prevent thromboembolism. In addition to its specific interactions with components of the coagulation system, heparin has numerous side effects which are poorly understood but can give rise to serious problems in heparin treatment. Among these side effects are inhibition of inflammation, tumor propagation and fat resorption and regulatory effects on bone and lipid metabolism. In spite of its water solubility heparin is to more than 95% attached to membranes thereby altering their properties, e.g. heparin bound to endothelial cells can reduce the attachment of thrombocytes thereby reducing thrombus formation. Commercially available heparin is highly heterogeneous in respect to carbohydrate monomer composition and degree of sulfation or N-acetylation of the polymer. In an attempt to elucidate the acti on of heparin we use heparin degrading enzymes from different microorganisms newly isolated from soil and water samples from Europe and Asia for fragmentation of heparin into defined fragments. To investigate the heparin degradation qualitatively and to determine the activities of purified enzymes we have developed a convenient isotachophoresis technique. This method allows characterization of heparin and degradation products by means of conductivity and UV-absorbance of the products. Isotachophoresis was performed at pH 4,2 where sulphate groups are negatively charged and carboxylate groups are largely uncharged so that the relative conductivity is a measure for the degree of sulfation of a fragment. From the UV-absorption at 254 nm the presence of double bonds, indicative of lyase activity, can be derived. With these analytical techniques at hand new enzyme activities for heparin cleavage were detected in these organisms. Also various highly sulfated homogeneous heparin fragments ar e
Conference