Heparin is a glycosaminoglycan which occurs in many mammalian tissues and has important anticoagulant and thrombolytic properties.
The chemical structure is composed mainly of two disaccharide repeating units A & B. A is L-iduronic acid 2-suplhate linked α-(1,4) to 2-deoxy-2-sulfamido-D-galactose 6-sulphate while B is D-glucuronic acid β-(1,4) linked to 2-deoxy-2-sulfamido-D-glucose 6-sulphate.