Galactose sulfate

The molecules are helices having a twofold screw-axis, with an axial rise per disaccharide residue of 9.45 A (945 pm). The axes of the chains are parallel, and about equally spaced, but are not further organized into crystalline arrays. A hydrogen bond was proposed between the OH-3 group of the 2-acetamido-2-deoxy-D-glucose residues and 0-5 of the D-galactose 6-sulfate residues. 

As indicated later (see Section VI,8), on addition of the chloride of praseodymium, europium, or other lanthanides to mono- or poly-sac-charide phosphates in D20, the signals of carbon atoms substituted with phosphate groups are recognizable, as they are displaced, relative to the rest of the 13C-n.m.r. spectrum.155 However, this diagnostic method is not applicable to sulfated polysaccharides, as signal displacements were not observed on addition of praseodymium or europium chloride to a solution of a,/3-D-galactose 6-sulfate or its sodium salt.156... 

This enzyme [EC 3.1.6.4] acts on 6-sulfate groups of the A-acetylgalactosamine 6-sulfate moieties in chondroitin sulfate and the galactose 6-sulfate groups in keratan sulfate. 

Sulfotransferases917 920a transfer sulfo groups to O and N atoms of suitable acceptors (reaction type ID, Table 10-1). Usually, transfer is from the "active sulfate," 3 -phosphoadenosine 5 -phosphosuIfate (PAPS),921 whose formation is depicted in Eq. 17-38. Sulfatases catalyze hydrolysis of sulfate esters. The importance of such enzymes is demonstrated by the genetic mucopolysaccharidoses. In four of these disease-specific sulfatases that act on iduronate sulfate, heparan N-sulfate, galactose-6-sulfate, or N-acetylglu-cosamine-4-sulfate are absent. Some of these, such as heparan N-sulfatase deficiency, lead to severe mental retardation, some cause serious skeletal abnormalities, while others are mild in their effects.922... 

D. A. Navarro and C. A. Stortz, Determination of the configuration of 3,6-anhydrogalactose and cyclizable a-galactose 6-sulfate units in red seaweed galactans, Carbohydr. Res., 338 (2003) 2111-2118. 

Many details of this mechanism remain to be determined, but, even in schematic form, it explains several observations. Fig. 5 (see p. 289) and the accompanying text suggest that double-helix formation, and therefore gelation, would be completely blocked by the presence of D-galactose 6-sulfate or 2,6-disulfate in place of a 3,6-anhydride... 

Finally, mention should be made of another kind of sulfatase, extracted from a red alga. This sulfatase is not a hydrolase, but converts residues of L-galactose 6-sulfate within a particular polysaccharide, porphyran, into 3,6-anhydro-L-galactose residues, thus simulating the action of alkali. It is not yet known whether this enzyme will function on suitably sulfated oligosaccharides, or whether it is specific for the polysaccharide sulfate, porphyran. 

Acetamido-2-deoxy-D-glucose disulfate 2-Acetamido-2-deox3 -D-galactose 4-sulfate 2-Acetamido-2-deoxy-D-galactose 6-sulfate 2-Acetamido-2-deoxy-D-galactose disulfate... 

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