Chemical modification of glycosaminoglycan polysaccharides

The linear anionic class of polysaccharides, glycosaminoglycans (GAGs), are critical throughout the animal kingdom for developmental processes and the maintenance of healthy tis-sues. They are also of interest as a means of influencing biochemical processes. One member of the GAG family, heparin, is exploited globally as a major anticoagulant pharmaceutical and there is a growing interest in the potential of other GAGs for diverse applications ranging from skin care to the treatment of neurodegenerative conditions, and from the treatment and prevention of microbial infection to biotechnology. To realize the potential of GAGs, however, it is necessary to develop effective tools that are able to exploit the chemical manipulations to which GAGs are susceptible. Here, the current knowledge concerning the chemical modification of GAGs, one of the principal approaches for the study of the structure-function relationships in these molecules, is reviewed. Some additional methods that were applied successfully to the analysis and/or processing of other carbohydrates, but which could be suitable in GAG chemistry, are also discussed

Antithrombin stabilisation by sulfated carbohydrates correlates with anticoagulant activity

Thermal stabilisation of native antithrombin-III (AT), determined using differential scanning fluorimetry, correlated with the anticoagulant activity of heparin and heparin-related saccharides. Similar conformational changes were induced in native AT by a variety of active and inactive heparin-related sulfated carbohydrates, measured in solution using synchrotron radiation circular dichroism, and their anticoagulant activities. Measurement of native AT stabilisation provides a convenient assay for prospective anticoagulants and represents an additional parameter by which to compare biosimilar heparins.National Science Foundation's National High Magnetic Field Laboratory User Program in the Advanced Magnetic Resonance Imaging and Spectroscopy (AMRIS) Facility (McKnight Brain Institute, University of Florida, USA)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo UNIFESP, Dept Biochem, BR-04044020 São Paulo, BrazilDiamond Light Source Ltd, Beam Line Circular Dichroism 23, Didcot OX11 ODE, Oxon, EnglandUniv Liverpool, Dept Struct & Chem Biol, Liverpool L69 7ZB, Merseyside, EnglandIst Ric Chim & Biochim G Ronzoni, I-20133 Milan, ItalyUniv Fed Rio Grande do Norte, Dept Biochem, BR-59072970 Natal, RN, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Biochem, BR-04044020 São Paulo, BrazilWeb of Scienc

A heparin-like glycosaminoglycan from shrimp containing high levels of 3-O-sulfated D-glucosamine groups in an unusual trisaccharide sequence

The detailed characterization of a novel heparin-like glycosaminoglycan purified from the viscera (heads) of the shrimp Litopenaeus vannamei is reported. Structural analysis performed by mono-and two-dimensional nuclear magnetic resonance (NMR) spectroscopy revealed it to be rich in both glucuronic acid and N, 6-sulfated glucosamine residues. the key peculiarities were its high 3-O-sulfated glucosamine content compared to mammalian heparins; a residue which is usually associated with the antithrombin (AT) binding site, and the location of these residues within 2-O-sulfated iduronate and glucuronate-containing sequences (I(2S-)A*-G), a situation not found in mammalian heparin. It also exhibited higher molecular weight (similar to 36 kDa) than conventional heparin (similar to 16 kDa) but, negligible anticoagulant activity (similar to 5 IU/mg compared to heparin similar to 190 IU/mg) and stabilization of AT, which has been linked directly to anticoagulation activity. A high affinity fraction, eluting at a similar salt concentration (0.75-1.5 M NaCl) from an antithrombin affinity column, to the high affinity fraction of heparin, also showed only weak thermal stabilization of AT (+ similar to 2 degrees C). These structural peculiarities may help elucidate more clearly the relationship between structure and function of sulfated polysaccharides, and provide useful model compounds with which to better understand interactions of biological significance. (C) 2014 Published by Elsevier B.V.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The Ronzoni FoundationFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Univ Fed Rio Grande do Norte, Dept Bioquim, BR-59072970 Natal, RN, BrazilUniv Fed Rio Grande do Norte, Fac Ciencias Saude Trairi, Santa Cruz, CA USAUniversidade Federal de São Paulo, Dept Bioquim, São Paulo, BrazilUniv Liverpool, Dept Struct & Chem Biol, Liverpool L69 3BX, Merseyside, EnglandIst Ric Chim & Biochim G Ronzoni, Milan, ItalyUniversidade Federal de São Paulo, Dept Bioquim, São Paulo, BrazilCNPq: 20127503FAPESP: 2012/00850-1CAPES: 1301824Web of Scienc

A non-hemorrhagic hybrid heparin/heparan sulfate with anticoagulant potential

AbstractThe structural characterization and the anticoagulant potential of a novel heparin/heparan sulfate-like compound from the heads of Litopenaeus vannamei shrimp are described. While it is distinct from either heparin or heparan sulfate, enzymatic depolymerization and nuclear magnetic resonance spectroscopy analyses revealed that this molecule does share some structural features with heparin, such as the high degree of N- and 6-O-sulfation and minor N-acetylation, and with heparan sulfate, in the glucuronic acid content. Its ability to stabilize human antithrombin explains its significant anticoagulant activity in aPTT and Factor-Xa inhibition assays. Interestingly, in contrast to mammalian heparin, the shrimp compound displayed negligible hemorrhagic effect. Together, these findings have particular interest since they reveal a novel molecule with significant anti-Xa activity coupled with low bleeding effects which make the shrimp heparin/HS-like compound a potential alternative for mammalian heparin

A heparin-like compound isolated from a marine crab rich in glucuronic acid 2-O-sulfate presents low anticoagulant activity

A natural heparin-like compound isolated from the crab Goniopsis cruentata was structurally characterized and its anticoagulant and hemorrhagic activities were determined. Enzymatic and nuclear magnetic resonance analysis revealed that its structure is rich in disulfated disaccharides, possessing significant amounts of 2-O-sulfated-beta-D-glucuronic acid units. Furthermore, low amounts of trisulfated disaccharide units containing 2-O-sulfated-alpha-L-iduronic acid were detected, when compared to mammalian heparin. in addition, this heparin-like structure showed negligible in vitro anticoagulant activity and low bleeding potency, facts that make it a suitable candidate for the development of structure-driven, heparin based therapeutic agents with fewer undesirable effects. (C) 2013 Elsevier B.V. All rights reserved