Umbilical cord polysaccharide

Hyaluronic acid consists of repeating disaccharides of /3-D-glucopyranosyluronic acid-(l— 3)-iV-acetyl-D-galactosamine linked p- l 4) to the next disaccharide. This proteoglycan can have between 500 and 50,000 residues per chain [92]. Hyuronic acid is found widely distributed in mammalian cells and tissues, where it is found in synovial fluid that lubricates the joints, in the vitreous humor of the eye, and in connective tissue, such as the umbilical cord, the dermis, and the arterial wall. It also occurs as a capsular polysaccharide around certain bacteria, such as pathogenic streptococci [92]. 

Meyer K, Palmer JW, Smyth EM. Glycoproteins. II. The polysaccharides of vitreous humor and of umbilical cord. J Biol Chem 1936 114 689-703. Weissman B, Meyer K. The structure of hyalobiuronic acid and of hyaluronic acid from umbilical cord. J Am Chem Soc 1954 76 1753-1757. 

Hyaluronate. Synthetic polymers and polysaccharides have been subjected to dichroism studies for structural information (Liang and Marchessault, 1959b Pearson et al, 1960). Quinn and Bettelheim (1963) used such methods on sodium hyaluronate isolated from umbilical cords. Figures 6.7a and 6.7b show the spectrum of an oriented sodium hyaluronate film which has been elongated by 40%. Table 6.6 contains band assignments made by these workers based on data reported in the literature. 

Hyaluronic acid was first isolated by Karl Meyer from vitreous humor (30) and later from umbilical cord, synovial fluid, skin, cock s comb, certain fowl tumors, groups A and C hemolytic streptococci, and other sources 31). Historically, it has been a major and frequent if not universal component of Levene s so-called mucoitin sulfates. The polysaccharide acts in animal tissue presumably as an integral part of the gel-like ground substance of connective tissue (and other tissues). Another important function of hyaluronic acid in animals is serving as a lubricant and shock ab-sorbant in the joints. 

Hyaluronic acid is generally prepared from umbilical cords. Most of the protein is removed by digestion with pepsin and trypsin, and the residual protein is separated by the chloroform - amyl alcohol procedure. Hyaluronic acid may be precipitated by fractionation with ammonium sulfate in the presence of pyridine (32). This step also removes a contaminating polysaccharide sulfate. 

Over the next 10 years, Meyer and other authors isolated hyaluronan from various animal organs. For example, the polysaccharide was found in joint fluid, the umbilical cord and recently it has become possible to extract HA from almost all vertebrate tissues. In 1937, F. Kendall isolated hyaluronan from the capsules of streptococci groups A and C. This work had great scientific and practical importance, as today streptococci groups are the most economical and reliable source for the industrial production of hyaluronic acid [3]. 

Polysaccharides composed of the same monomers as chondroitinsulfuric acid and apparently closely related to it have been isolated from umbilical cord (271) and from pig skin (268). The polysaccharides from both these sources, however, unlike the chondroitinsulfuric acid of cartilage, showed resistance to hydrolysis with a preparation of testicular hyaluronidase, and also had different optical rotations. 

Hyaluronan has been detected in varying concentrations in all vertebrate tissues analyzed [1-3]. The highest concentrations are usually found in loose connective tissues such as synovial fluid, umbilical cord, the vitreous body and skin (0.1-10 mg/ml). HA has therefore been designated as a connective tissue polysaccharide. However, significant amounts have also been described in brain, muscles, liver etc. The lowest concentrations are found in the circulation (10-100 ng/ml) and this is due to a very effective removal of the polysaccharide from blood in the liver sinusoids. HA is usually not seen in invertebrates [58] but it was early observed that certain bacteria can synthesize HA [4]. 

A chondroitin sulfate possessing properties slightly different from those of chondroitin 4-sulfate has been isolated from human umbilical cord, tendon, cartilage, heart valve, skin, nucleus pulposus, saliva, and from a chordoma. The material obtained from the latter two sources is probably a pure polysaccharide, whereas material obtained from the other sources seems not to be free of chondroitin 4-sulfate. A pol ccharide sulfate obtained from References p. tgs... 

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