Chapter 5 Methods for Isolation and Characterization of Sulfated Glycosaminoglycans from Marine Invertebrates Mariana P. Stelling, Ananda A. de Bento, Philippe Caloba, Eduardo Vilanova, and Mauro S. G. Pava ˜o Abstract Marine invertebrates produce different kinds of sulfated polysaccharides. These glycans play essential roles in several biological processes and the study of these molecules is promising in a variety of fields. In the following sections, we describe the materials and methods used for the extraction, purification, and characterization of marine invertebrate-derived glycosaminoglycans. Key words Sulfated glycosaminoglycans, Marine invertebrates, Sulfated polysaccharide characteriza- tion, Polysaccharide purification, Nuclear magnetic resonance 1 Introduction Marine invertebrates produce different kinds of sulfated polysac- charides. These glycans play essential roles in several biological processes such as tissue integrity, fertilization, infection, inflamma- tion, cell growth, and others. Invertebrates from several phyla of the marine biodiversity have been used in different studies, and as sources of new products with natural bioactive properties. For example, ascidians, sea cucumbers, and bivalve mollusks are poten- tial sources of antitumor, antimicrobial, anticoagulant, antithrom- botic, and anti-inflammatory glycosaminoglycan-like compounds. Ascidians, also known as tunicates, are evolved sessile filter feeder marine animals belonging to the phylum Chordata, subphy- lum Urochordata. They may form colonies or occur as solitary individuals [1]. Ciona intestinalis, Phallusia nigra, and Styela pli- cata are the primary species of ascidians whose glycosaminoglycans have been extensively studied. These species are usually found in shallow waters attached to rocks. One of the main characteristics of ascidians is the presence of an outer tunic that protects and sustains the animal’s body. Different types of sulfated polysaccharides have Davide Vigetti and Achilleas D. Theocharis (eds.), The Extracellular Matrix: Methods and Protocols, Methods in Molecular Biology, vol. 1952, https://doi.org/10.1007/978-1-4939-9133-4_5, © Springer Science+Business Media, LLC, part of Springer Nature 2019 55