Abreu WS Soares PAG Motta JM Kozlowski EO Teixeira FCOB Soares MA Borsig L Mourão PAS Pavão MSG 2019 Heparin or highly sulfated heparan sulfate (HS) has been described in different invertebrates. In ascidians (Chordata-Tunicata), these glycosaminoglycans occur in intracellular granules of oocyte accessory cells and circulating basophil-like cells, resembling mammalian mast cells and basophils, respectively. HS is also a component of the basement membrane of different ascidian organs. We have analyzed an HS isolated from the internal organs of the ascidian Phallusia nigra, using solution 1H/13C NMR spectroscopy, which allowed us to identify and quantify the monosaccharides found in this glycosaminoglycan. A variety of α-glucosamine units with distinct degrees of sulfation and N-acetylation were revealed. The hexuronic acid units occur both as α-iduronic acid and β-glucuronic acid, with variable sulfation at the 2-position. A peculiar structural aspect of the tunicate HS is the high content of 2-sulfated β-glucuronic acid, which accounts for one-third of the total hexuronic acid units. Another distinct aspect of this HS is the occurrence of high content of N-acetylated α-glucosamine units bearing a sulfate group at position 6. The unique ascidian HS is a potent inhibitor of the binding of human colon adenocarcinoma cells to immobilized P-selectin, being 11-fold more potent than mammalian heparin, but almost ineffective as an anticoagulant. Thus, the components of the HS structure required to inhibit coagulation and binding of tumor cells to P-selectin are distinct. Our results also suggest that the regulation of the pathway involved in the biosynthesis of glycosaminoglycans suffered variations during the evolution of chordates. application/pdf https://sonar.ch/global/documents/47546 eng info:eu-repo/semantics/altIdentifier/doi/10.3390/md17060351 info:eu-repo/semantics/altIdentifier/pmid/31212795 info:eu-repo/semantics/openAccess Marine drugs. - 2019 P-selectin ascidian glycosaminoglycans cancer coagulation heparan sulfate marine biology nuclear magnetic resonance Adenocarcinoma Animals Anticoagulants Cell Line, Tumor Colon Colonic Neoplasms Glucuronates Glucuronic Acid Glycosaminoglycans Heparin Heparitin Sulfate Humans P-Selectin Urochordata Tunicate Heparan Sulfate Enriched in 2-Sulfated β-Glucuronic Acid: Structure, Anticoagulant Activity, and Inhibitory Effect on the Binding of Human Colon Adenocarcinoma Cells to Immobilized P-Selectin. http://purl.org/coar/resource_type/c_6501