Ruggiero, J.Fossey, Marcelo Andrés [UNESP]Santos, J. A.Mourao, P. A. S.2014-05-202014-05-201998-02-01Carbohydrate Research. Oxford: Elsevier B.V., v. 306, n. 4, p. 545-550, 1998.0008-6215http://hdl.handle.net/11449/37118Calcium binding and charge distribution on highly branched and linear sulfated L-galactans from ascidians have been studied using a metallochromic indicator and conductimetric titrations. The distance between charged groups of the linear and highly branched galactans does not vary despite their marked differences in sulfate/total sugar molar ratios. These results indicate that the sulfated L-galactose units are concentrated in the central polysaccharide core and not intercalated among non-sulfated units. This inference is consistent with the chemical studies of these galactans. Surprisingly, calcium affinity increases with increasing amounts of non-sulfated sugar branches in the molecule. Thus, calcium binding in these polymers is not a simple function of availability of anion binding sites but a more complex calcium-polysaccharide interaction. (C) 1998 Elsevier B.V. Ltd. All rights reserved.545-550engArtigo10.1016/S0008-6215(97)10100-8WOS:000075389500009Acesso restrito4101562077663619