COORDINATION ABILITY OF DIGALACTOSAMINE, AND DIGALACTURONIC AND TRIGALACTURONIC ACIDS - POTENTIOMETRIC AND SPECTROSCOPIC STUDIES OF CU(II) COMPLEXES

Potentiometric and spectroscopic (EPR, CD, and absorption spectra) dat a obtained for digalactosamine and di- and trigalacturonic acid with C u(II) have shown that the di-sugar binding is usually less efficient t han that of monomeric units while the tri-sugar can probably simultane ously use two terminal subunits to coordinate a metal ion. The latter result may have some relevance for metal binding by polysaccharides. A ll sugar ligands use amino or carboxylate functions as an anchor site, as in monomeric units. Bulky oligomeric ligands protect formation of the bis complexes. This causes the hydrolysis to be a dominant process at higher pH.