Free-radical depolymerization of glycosaminoglycan from sea cucumber Thelenata ananas by hydrogen peroxide and copper ions

A process of depolymerization of a new fucosylated chondroitin sulfate from Thelenata ananas by free radicals was developed. The fractions with different molecular weights and narrow molecular weight distribution were obtained. The parameters of the process were investigated by high-performance gel permeation chromatography. The kinetics of the depolymerization of THG by H2O2 was studied, and a possible mechanism was proposed. The results indicated that the levels of final products fragmentation and reproducibility were different depending on the conditions of depolymerization used. The fragmentation of the main chain of THG occurred randomly and obeyed pseudo-first-order kinetics, and produced species with rather narrow and unimodal distribution of molar mass. Chemical compositions of partially depolymerized samples by H-1/C-13 nuclear magnetic resonance spectroscopy and by elementary analyzer suggested that there was no preferential cleavage of sulfated alpha-L-fucopyranose side-chain, and chemical composition of products was kept almost unchanged from that of native THG. (C) 2010 Elsevier Ltd. All rights reserved.