A method for at least partial deacetylation of a biopolymer comprising acetyl groups, including: a1) providing a biopolymer including acetyl groups; a2) reacting the biopolymer including acetyl groups with hydroxylamine (NH.sub.2OH) or a salt thereof at a temperature of 100° C. or less for 2-200 hours to form an at least partially deacetylated biopolymer; and a3) recovering the at least partially deacetylated biopolymer.

[Problem to be Solved]

The importance of sugar chains having α2,3- or α2,6-linked sialic acid at their non-reducing ends is known. Industrial production has been demanded for these sugar chain compounds. Particularly, the production of glycoprotein drugs or the like inevitably requires producing in quantity sugar chains having homogeneous structures by controlling the linking pattern (α2,6-linkage or α2,3-linkage) of sialic acid. Particularly, a triantennary or tetraantennary N-type complex sugar chain having sialic acid at each of all non-reducing ends is generally considered difficult to chemically synthesize. There has been no report disclosing that such a sugar chain was chemically synthesized. Furthermore, these sugar chains are also difficult to efficiently prepare enzymatically.

[Solution]

The present inventors have newly found the activity of sialyltransferase of degrading sialic acid on a reaction product in the presence of CMP and also found that formed CMP can be degraded enzymatically to thereby efficiently produce a sialic acid-containing sugar chain. The present inventors have further found that even a tetraantennary N-type sugar chain having four α2,6-linked sialic acid molecules, which has previously been difficult to synthesize, can be prepared at high yields by one-pot synthesis comprising the elongation reaction of a biantennary sugar chain used as a starting material without performing purification after each enzymatic reaction.

The invention relates to glucosaminoglycan derivatives, endowed with heparanase inhibitory activity and antitumor activity, bearing carboxylate groups in positions 2 and 3 of at least part of the glucosaminoglycan residues, and to the process for preparing the same. The glucosaminoglycan derivatives of the present invention are generated starting from natural or synthetic glucosaminoglycans, preferably heparin or low molecular weight heparin, optionally 2-O- and 2N-desulfated by two steps of oxidation. By the first oxidation, adjacent diols and optionally adjacent OH/NH2 of the glucosaminoglycan residues are converted to aldehydes and by the second oxidation said dialdehydes are converted to carboxylate groups. The first oxidation preferably leads to the cleavage of C2-C3 linkage of the ring of oxidable residues. The invention further relates to a process for the preparation of said glucosaminoglycan derivatives and further to their use as active ingredients of medicaments. Furthermore, the invention relates to pharmaceutical compositions comprising di/tricarboxylated heparin derivatives, as active agent.

A glycosaminoglycan derivative which is obtainable by a process that includes the steps of N-desulfation of from 25% to 100% of the N-sulfated residues of a glycosaminoglycan, and oxidation, by periodate at a pH of from 5.5 to 10.0, of from 25% to 100% of the 2-N-, 3-O-non-sulfated glucosamine residues, and of the 2-O-non-sulfated uronic acid residues of said glycosaminoglycan, under conditions effective to convert adjacent diols and adjacent OH/NH.sub.2 to aldehydes. The process further includes reduction, by sodium borohydride, of said oxidized glycosaminoglycan, under conditions effective to convert said aldehydes to alcohols, where the glycosaminoglycan is heparin, low molecular weight heparin, heparan sulfate or fractions thereof.

Oligosaccharides from bovine milk, whey and dairy products, and methods of producing bovine milk oligosaccharides are provided.

The present invention concerns a block copolymer having at least one oligo- or polysaccharide block and at least one elastin-like polypeptide block, wherein said block copolymer comprises at least one repetitive unit having the following formula (I):

##STR00001##

wherein R′ is the side chain of a natural or synthetic amino acid other than proline and derivatives thereof.

A method of preparing a hydrogel product comprising crosslinked glycosaminoglycan molecules, said method including: i) providing a glycosaminoglycan crosslinked by amide bonds, wherein the crosslinked glycosaminoglycans include ester crosslinks formed as byproducts during the amide crosslinking; and ii) subjecting the crosslinked glycosaminoglycans to alkaline treatment to hydrolyze ester crosslinks formed as byproducts during the amide crosslinking.

A method for at least partial deacetylation of a biopolymer comprising acetyl groups, including: a1) providing a biopolymer including acetyl groups; a2) reacting the biopolymer including acetyl groups with hydroxylamine (NH.sub.2OH) or a salt thereof at a temperature of 100° C. or less for 2-200 hours to form an at least partially deacetylated biopolymer; and a3) recovering the at least partially deacetylated biopolymer.

Provided herein is an E. coli O polysaccharide, O25B. Also provided herein are prokaryotic host cells containing enzymes (e.g., glycosyltransferases) used in O25B production. The host cells provided herein produce O25B bioconjugates, wherein said bioconjugates contain O25B linked to a carrier protein. Further provided herein are compositions, e.g., pharmaceutical compositions, including O25B and/or bioconjugates containing O25B. Such compositions can be used as vaccines against infection with ExPEC, and may further include one or more additional bioconjugates.

A crosslinked polymeric network is disclosed. The crosslinked polymeric network comprises a reaction product of a first glycosaminoglycan, a second glycosaminoglycan, and a crosslinking agent, wherein the first glycosaminoglycan is different than the second glycosaminoglycan.