Heparinoids are glycosaminoglycans which are derivatives of heparin. They include oligosaccharides and sulfated polysaccharides of plant, animal, or synthetic origin. One study conducted on heparinoids. Heparinoids are glycosaminoglycans which are derivatives of heparin. They include oligosaccharides and sulfated polysaccharides of plant, animal, or synthetic origin. One study conducted on heparinoids. Heparinoids, like heparin, act by interacting with heparin binding proteins, generally through ionic interactions or hydrogen bonding. Some examples of heparin binding proteins include antithrombin III. It is thought that much protein interaction with heparin is not direct, and instead heparin binding protein actually interact with glycosaminoglycan (GAG) side chains or mucins bound to the heparin polymer, so it is possible that heparinoids interact with these proteins in a similar way, acquiring GAG side chains in vivo. One counter example is the protein chymase, which directly binds to heparin. Dermatan sulfate is one example of a compound that is classified as a heparinoid. It is a naturally-occurring polysaccharide of O-sulfonated N-Acetyl-D-galatosamine, L-induronic acid, and D-glucuronic acid that has been clinically used as an antithrombic agent. Chondroitin sulfate shows slightly less biological activity than dermatan sulfate, and is composed of O-sulfonated N-Acetyl-D-galatosamine and D-glucuronic acid. It is theorized that this change in efficacy is related to the absence of L-induronic acid, which affects the flexibility of the polymer chain. Acharan sulfate is a heparinoid that is naturally produced by the giant African land snail, Achatina fulica. Keratan sulfate is a heparinoid that is a component of cartilage. It is found in the cornea. Chitin, a component of insect shells and fungal structures, can be de-N-acetylated to form chitosan, which when sulfonated has a significant chemical similarity to heparin. In fact, it inhibits thrombin by affecting ATIII. Lepirudin is a recombinant preparation of the polypeptide anticoagulant secreted by leeches and is used in patients with heparin induced thrombocytopenia. Fucoidin is a polymer composed of sulfated L-fucose. Carrageenans are isolated from algae.