N-Glucurone

II. The Methyl Ethers of d-Glucuronic Acid 1. 3-0-Melhyl-n-glucuronic Add... 

Substances° (Other Than Those in Table III) Whose Administration Has Been Reported to Increase the Urinary D-Glucuronic Acid or for which Other Evidence of n-Glucuronic Conjugation Exists... 

Source Mode of linkage of l-arabinofuranose end-groupsa Mode of linkage of n-glucuronic acid end-groupsb Other structural features Refer- ences... 

The uridine diphosphate ester derivatives in a non-capsulated. Type II pneumococcus and a capsulated. Type III pneumococcus were investigated by Smith, Mills, and Harper." The capsule of the Type III pneumococcus is composed of a polysaccharide having 4-0-( 8-D-glucopyranosyluronic acid)-D-glucose as a repeating unit. n-Glucuronic acid, D-glucose, and L-rhamnose are constituents of the capsular polysaccharide of the Type II pneumococcus. 

The presence of uridine 5-(D-glucosyluronic acid dihydrogen pyrophosphate) in both pneumococci indicates that this compound mediates the transfer of n-glucuronic acid to n-glucose (as the acceptor), giving rise to the repeating disaccharide unit of the capsular polysaccharide. The isolation of identical uridine nucleotides from both types indicates that the failure of the Type-II strain to produce capsular polysaccharide resides in a subsequent conjugation step or an even later polymerization step. 

These materials are also called aminopolysaccharides by Kent (K15, K16) or mucopolyuronides by Blix (B22). They contain uronic (hexu-ronic) acid, usually n-glucuronic acid. Only one other uronic acid occurring together with n-glucuronic acid, namely t-iduronic acid, has been found in chondroitin sulfate B (dermatan). In addition to uronic acid, most of these materials, with the exception of hyaluronic acid, contain sulfates (in ester form). They also contain hexosamine as glucosamine or galactosamine, frequently in acetylated form. 

Many hemicelluloses are known to consist of n-glucuronic acid, combined with n-xylose, L-arabinose, or both and to contain no hexose. A few hemicelluloses have been reported to contain n-galacturonic acid, n-glucose, n-mannose or n-galactose. - - Since pectic materials and cellulosans often dissolve in the alkaline solution used in extracting the hemicelluloses, it is quite possible that the galacturonic acid and hexoses may be derived from these materials and not from hemicelluloses. 

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. ... 

Complete hydrolysis of hyaluronate by a crude testicular extract produces A -acetyl-n-glucosamine and n-glucuronic acid. For partial hydrolysis of the polysaccharide, pneumococcal and testicular hyaluronidases are useful. 

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