1 1 . M U C O P O L Y S A C C H A R I D E S IN TISSUE C U L T U R E
357
mucopolysaccharide molecule is maintained in the extended state
by the mutual repulsion between the negatively charged groups,
whereas in the presence of cations it assumes a more random configuration. As Dorfman and Schiller (1958), amongst others, have pointed
out, these effects may be of physiological importance. Such molecules
must influence the transport of ions and water through the ground
substance, to an extent determined by the physical state of the mucopolysaccharide which, in turn, is defined by the ionic environment.
All mucopolysaccharides, by definition, contain hexosamine—either
glucosamine or galactosamine. These are the only amino sugars that
have been established as definite and major components of animal
acid mucopolysaccharides. Talosamine has been isolated from cartilage
(Muir, 1957; Crumpton, 1957). It has not yet been established,
however, whether this is a natural component of the cartilage mucopolysaccharide, or is an artifact (Bettelheim-Jevons, 1958).
In most of the acid mucopolysaccharides, the uronic acid component
is glucuronic acid. In chondroitin sulphate-B, iduronic acid occurs
(Hoffman, Linker and Meyer, 1956). This has been shown to be Liduronic acid by degradation and synthesis of a derivative (Stoffyn
andjeanloz, 1960).
Suzuki and Strominger (1960c) point out that in most chondroitin
sulphate preparations, the sulphate content is less than the theoretical
value for one sulphate per acetyl galactosamine residue. In addition,
their results suggest that some acetylgalactosamine disulphate residues
may also occur in certain chondroitin sulphate molecules. The commonly accepted structure of chondroitin sulphate, therefore, may be
only a statistical model of a compound that contains a small number
of non-sulphated and disulphated, as well as monosubstituted disaccharides. A chondroitin sulphate-D (Suzuki, 1960) has been obtained
from shark cartilage which has an infra-red spectrum similar to that
of chondroitin sulphate-C (Nakanishi, Takahashi and Egami, 1955),
but which has an excessively high sulphur content equivalent to 1-3
sulphate groups/mole acetylgalactosamine.
In addition to the acid mucopolysaccharides, there are also neutral
mucopolysaccharides, which occur in firm combination with protein
or peptides, and are found widely distributed in body fluids (serum,
plasma, urine), glandular and epithelial secretions (e.g. milk, gastric
mucin, nasal and cervical mucins, bile and sputum, submaxillary and
salivary mucoid), skin and connective tissues (Meyer, Smyth and Palmer,
1937; Werner, 1953; Gottschalk, 1957; Gottschalk and Graham, 1959;
Herring and Kent, 1958; Schultz-Handt and Eig-Larson, 1961).
These polysaccharides, which include the blood-group polysaccharides
(reviewed by Kabat, 1956) contain neither uronic acid nor ester
357
mucopolysaccharide molecule is maintained in the extended state
by the mutual repulsion between the negatively charged groups,
whereas in the presence of cations it assumes a more random configuration. As Dorfman and Schiller (1958), amongst others, have pointed
out, these effects may be of physiological importance. Such molecules
must influence the transport of ions and water through the ground
substance, to an extent determined by the physical state of the mucopolysaccharide which, in turn, is defined by the ionic environment.
All mucopolysaccharides, by definition, contain hexosamine—either
glucosamine or galactosamine. These are the only amino sugars that
have been established as definite and major components of animal
acid mucopolysaccharides. Talosamine has been isolated from cartilage
(Muir, 1957; Crumpton, 1957). It has not yet been established,
however, whether this is a natural component of the cartilage mucopolysaccharide, or is an artifact (Bettelheim-Jevons, 1958).
In most of the acid mucopolysaccharides, the uronic acid component
is glucuronic acid. In chondroitin sulphate-B, iduronic acid occurs
(Hoffman, Linker and Meyer, 1956). This has been shown to be Liduronic acid by degradation and synthesis of a derivative (Stoffyn
andjeanloz, 1960).
Suzuki and Strominger (1960c) point out that in most chondroitin
sulphate preparations, the sulphate content is less than the theoretical
value for one sulphate per acetyl galactosamine residue. In addition,
their results suggest that some acetylgalactosamine disulphate residues
may also occur in certain chondroitin sulphate molecules. The commonly accepted structure of chondroitin sulphate, therefore, may be
only a statistical model of a compound that contains a small number
of non-sulphated and disulphated, as well as monosubstituted disaccharides. A chondroitin sulphate-D (Suzuki, 1960) has been obtained
from shark cartilage which has an infra-red spectrum similar to that
of chondroitin sulphate-C (Nakanishi, Takahashi and Egami, 1955),
but which has an excessively high sulphur content equivalent to 1-3
sulphate groups/mole acetylgalactosamine.
In addition to the acid mucopolysaccharides, there are also neutral
mucopolysaccharides, which occur in firm combination with protein
or peptides, and are found widely distributed in body fluids (serum,
plasma, urine), glandular and epithelial secretions (e.g. milk, gastric
mucin, nasal and cervical mucins, bile and sputum, submaxillary and
salivary mucoid), skin and connective tissues (Meyer, Smyth and Palmer,
1937; Werner, 1953; Gottschalk, 1957; Gottschalk and Graham, 1959;
Herring and Kent, 1958; Schultz-Handt and Eig-Larson, 1961).
These polysaccharides, which include the blood-group polysaccharides
(reviewed by Kabat, 1956) contain neither uronic acid nor ester