Mannose from heparin

From pig mucosa. Notations as for Scheme 1. Major products (yield 40-80% of original heparin). Major disaccharide fraction (50-80%). From heparin chains terminating with a D-glucuronic acid residue at the reducing end. Minor products (yield <3% of original heparin). From the active site for antithrombin (asterisk denotes 3-C-sulfation of the amino sugar or anhydro-D-mannose). 

Deamination studies have aided attempts to locate the positions of the O-sulfate groups in heparin. From the results of deamination and periodate-oxidation studies, it was concluded239 that half of the uronic acid residues are sulfated at C-2, and sequential periodate oxidation, reduction with sodium borohydride, acid treatment, and deamination gave 2,5-anhydro-D-mannose 6-sulfate.240,241 Sulfated O-(hexosyluronic acid)-2,5-anhydro-D-mannose and sulfated uronic acids were subsequently isolated, and the isolation (in 65% yield) of the disulfated 0-(idosyluronic acid)-2,5-anhydro-D-mannose (137) from heparin, together with the 13C n.m.r. spectra of 137 and heparin, suggested243 that at least two thirds of the heparin structure consists of the repeating unit 138. 

In the disaccharide with a-L-iduronic-acid-2-sulfate linked to the 4-OH of 2,5-anhydro-mannose, which is obtained from heparin by nitrous acid degradation, the conformation of the iduronic acid was found to be C4 and to be independent of temperature in the range from 20 °C to 90 °C [217]. 

The second class of proteins that seem to bind mannose 6-phosphate and sulfated oligosaccharides derived from heparin are the seminal plasma spermadhesins, a group of small, structurally well defined proteins with possible biological function in sperm capacitation and sperm-egg interaction [236,237]. 

Using this procedure, Consden and Stanier were able to show that a hydrolyzate of Group A hemolytic streptococci contained hexosamine, rhamnose, ribose, and glucose and, also, that a hydrolyzate of purified, human fibrin contained uronic acid, hexosamine, mannose, and galactose. A similar combination of techniques has been employed by Woodin in a study of the composition of a comeal mucopolysaccharide. It is of interest that the conditions of acidic hydrolysis necessary for releasing the n-glucos-amine moiety from heparin also result in destruction of the concomitantly released n-glucuronic acid. Traces of the intact uronic acid may be revealed by zone electrophoresis of the hydrolyzates. ... 

Chapter 9. A substrate used in the assay of L-iduronic acid 2-sulphate sulphatase was obtained from sodium heparinate by methanolysis followed by nitrosation. Disaccharide monosulphates presumed to contain D-(methyl a-L-idopyranosiduronate-2-sulphate)-(l 4)-2,5-anhydro-D-mannose were isolated by gel filtration. Brucine L-guluronate and o-mannuronate, on the other hand, were obtained by treatment with brucine of the barium salts of the acids formed on hydrolysis of alginic add. ... 

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