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Three new diterpenoids, 2-O-lactoylborapetoside B (1), 6'-O-lactoylborapetoside B (2), and tinocrispol A (3), and nine known diterpenoids (4-12) were isolated from an EtOH extract of Tinospora crispa vines. Their structures were elucidated by spectroscopic analyses. The C-6 glucosyloxy group in borapetoside C (6) was revised to be α-oriented. The in vivo(More)
Two new sesquiterpene hydroquinones, polyfibrospongols A (1) and B (2), were isolated from the Taiwanese marine sponge Polyfibrospongia australis Lendenfeld (Spongiidae) in addition to the known metabolites, dictyoceratin A (3), ilimaquinone (4), and 5-epi-ilimaquinone (9). The structures of these compounds have been determined mainly on the basis of(More)
The sulfation at the 3-OH position of glucosamine is an important modification in forming structural domains for heparan sulfate to enable its biological functions. Seven 3-O-sulfotransferase isoforms in the human genome are involved in the biosynthesis of 3-O-sulfated heparan sulfate. As a rare modification present in heparan sulfate, the availability of(More)
A targeted heptasaccharide library was synthesised to prepare a heparan sulphate (HS) microarray. The array was probed with two glycan-binding proteins, HS 3-O-sulphotransferase 1 and antithrombin, demonstrating the binding selectivity between HS and proteins. The HS microarray technique will accelerate the understanding of the structure and function(More)
Low-molecular-weight heparins (LMWHs) are carbohydrate-based anticoagulants clinically used to treat thrombotic disorders, but impurities, structural heterogeneity or functional irreversibility can limit treatment options. We report a series of synthetic LMWHs prepared by cost-effective chemoenzymatic methods. The high activity of one defined synthetic LMWH(More)
A heparin oligosaccharide having a completely natural structure was successfully synthesized through a chemoenzymatic approach using an unnatural glycosyl acceptor, p-nitrophenyl glucuronide (GlcA-pNP). The use of an inexpensive and commercially available GlcA-pNP acceptor facilitates oligosaccharide recovery and purification on C-18 resin during(More)
Heparan sulfate and heparin are highly sulfated polysaccharides that consist of a repeating disaccharide unit of glucosamine and glucuronic or iduronic acid. The 2-O-sulfated iduronic acid (IdoA2S) residue is commonly found in heparan sulfate and heparin; however, 2-O-sulfated glucuronic acid (GlcA2S) is a less abundant monosaccharide (∼<5% of total(More)
A chemoenzymatic approach for synthesizing heparan sulfate oligosaccharides with a reactive diazoacetyl saccharide residue is reported. The resultant oligosaccharides were demonstrated to serve as specific inhibitors for heparan sulfate sulfotransferases, offering a new set of tools to probe the structural selectivity for heparan sulfate-binding proteins.
The L-iduronic acid (IdoA) residue is a critically important structural component in heparan sulphate polysaccharide for the biological functions. The pyranose ring of IdoA is present in (1)C4-chair, (2)SO-skew boat, and less frequently, in (4)C1-chair conformations. Here, we analyzed the conformation of IdoA residue in eight hexasaccharides by NMR. The(More)
Heparan sulfate (HS) is an abundant polysaccharide in the animal kingdom with essential physiological functions. HS is composed of sulfated saccharides that are biosynthesized through a complex pathway involving multiple enzymes. In vivo regulation of this process remains unclear. HS 2-O-sulfotransferase (2OST) is a key enzyme in this pathway. Here, we(More)
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