Abstract: Glycosaminoglycans derived from the K5 polysaccharide having high anticoagulant and antithrombotic activity obtained by a process comprising the preparation of the K5 polysaccharide from Escherichia coli, N-deacetilation/N-sulfation, C-5 epimerization, supersulfation, selective O-desulfation, selective 6-O sulfation and N-sulfation, wherein said epimerization is carried out using the glucuronosyl C-5 epimerase enzyme in solution or in immobilized form in presence of specific divalent cations.

Abstract: The purification of the E.coli K5 polysaccharide by treatment with isopropyl alcohol and elimination of lipophilic substances is described. The purified product can be used to prepare, after N-deacetylation, new N,O-sulfated polysaccharides with high degree of sulfation.

Abstract: New process for the preparation of chondroitin sulfates from the bacterial origin polysaccharide named K4, by defructosilation followed by selective sulfation.

Abstract: Glycosaminoglycans derived from K5 polysaccharide having high anticoagulant and antithrombotic activities are obtained by a process comprising the preparation of the K5 polysaccharide from Escherichia Coli, N-deacetylation/N-sulfation, C5 epimerisation, oversulfation, selective O-desulfation, selective 6-O sulfation and N-sulfation, in which said epimerisation is performed with the use of the enzyme glucuronosyl C5 epimerase in solution or immobilised in presence of specific divalent cations. New, particularly interesting compounds are obtained by controlling the reaction time in the O-desulfation step.

Abstract: Glycosaminoglycans derived from K5 polysaccharide having high anticoagulant and antithrombotic activity and useful for the control of coagulation and as antithrombotic agents are obtained starting from an optionally purified K5 polysaccharide by a process comprising the steps of N-deacetylation/N-sulfation, C5 epimerization, O-oversulfation, selective O-desulfation, 6-O-sulfation, N-sulfation, and optional depolymerization, in which said epimerization is performed with the use of the enzyme glucoronosyl C5 epimerase in solution or in immobilized form in the presence of divalent cations. New, particularly interesting antithrombin compounds are obtained by controlling the reaction time in the selective O-desulfation step and submitting the product obtained at the end of the final N-sulfation step to depolymerizazion.

Abstract: Process for the preparation of O-sulfated K4, K5 and K40 polysaccharides useful for the treatment of tumoral, HIV-1 and coagulation pathologies and in cosmetic preparations, wherein the K4, K5 or K40 polysaccharide in the form of sodium salt is suspended in an aprotic solvent and directly submitted to the reaction of O-sulfation with a pyridine-sulphur trioxide or trimetylamine-sulphur trioxide adduct or with chlorosulfonic acid.

Abstract: Derivatives of the K5 polysaccharide having anticoagulant activity higher than heparin, obtained by a process including the steps of reacting: with an organic base a solution of K5 polysaccharide N-deacetylated, N-sulfated and epimerized at least to an iduronic acid content of 50% treating with a sulfating agent to obtain the N-resulfation of the possible N-desulfated groups.

Abstract: Process for the preparation of polysaccharides having a high iduronic acid content comprising:a) N-deacetylation of the polysaccharide K5 from E. coli or of the heparan sulfate or O-desulfation of heparin or heparan sulfate;b) N-sulfation of the product obtained from the stage a);c) epimerization in presence of the C5 epimerase enzyme;d) sulfation of at least some free hydroxy groups, wherein the stage c) is carried out in a reaction medium constituted by a classical buffer solution formed by HEPES, potassium chloride, EDTA and TRITON X-100 to which a suitable additive is added.

Abstract: Heparins, heparin fractions or fragments, optionally salified with pharmaceutically acceptable cations, having molecular weight ranging from 1.000 to 30.000 D, characterized by an EDTA content lower than 0.1%, by the absence, in the .sup.1 H--NMR spectra, of the signals due to EDTA between 2.50 and 4.00 p.p.m. and substantially free from bleeding effect and optionally free from signals, in the .sup.13 C--NMR spectrum, from 80 to 86 ppm.