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d-Glucosamine derivatives bearing latent O4 functionality provide modified H/HS-type disaccharide donors for a final stage capping approach enabling introduction of conjugation-suitable, non-reducing terminal functionality to biologically important glycosaminoglycan oligosaccharides. Application to the synthesis of the first O4-terminus modified synthetic LMWH decasaccharide and an HS-like dodecasaccharide is reported.

Misfolded protein amyloid-beta protein (Aβ) and tau protein are two high hallmarks of Alzheimer's disease (AD), representing significant targets in treating AD. Researches on mechanisms of the two proteins inducing neuron dysfunctions provide therapeutic strategies of AD, including inhibition of Aβ production and aggregation, acceleration of Aβ clearance as well as reduction of tau hyperphosphorylation. Proteoglycans (PGs) consist of a core protein and glycosaminoglycans (GAGs) chains, with enormous structural diversity due to variation in the core protein, the number of GAGs chains as well as extent and position of sulfation. Considerable evidences have indicated that PGs and GAGs play important roles in Aβ and tau processing. Numbers of GAGs and analogues have potential therapeutic function in AD. In this Review, we focus on the relationship of PGs and GAGs with misfolded proteins in AD and their potential therapeutic implications.

Heparin, the glycosaminoglycan (GAG), was isolated from mollusk Katelysia opima (bivalve). The crude extract was partially purified by DEAE cellulose fractionation using two different molar concentrations of saline solution. Among the fractions F1, F2, F3 and F4, fraction F3 had highmolecular weight and better activity. F3 was further processed to get low-molecular weight heparin (LMWH) by nitrous acid depolymerization, and the total yield was 1.2 g/kg. The crude unfractionated heparin (UFH), fractionated heparin and depolymerized heparin samples were colorimetrically analyzed for the metachromatic shift using azure-A dye, and all the samples were found to be metachromatically active. Both UFH and LMWH showed an anticoagulant activity of 160 USP U/mg. Fractionated molluscan and LMWH were found to have peaks similar to that of standard heparin when assessed by the FTIR spectrum. Finally, molecular weight was determined by gradient polyacrylamide gel electrophoresis for UFH, fractionated F3 and LMWH, which were found to be 31,000, 30,500 and 6000 Da, respectively., (Copyright 2008 Prous Science, S.A.U. or its licensors. All rights reserved.)