Galactose-specific receptor

Schauer, R., Fischer, C., Kluge, A., Lee, H., and Ruch, B., 1990, Mechanism of binding and uptake of sialidase-treated blood cells and glycoproteins by the galactose-specific receptor of rat peritoneal macrophages, Biomed. Biochim. Acta 49 S230-S235. 

Cell division is stimulated by lectins (for a review, see Ref. 188) and by other saccharide-directed reagents, for example, sodium periodate and D-galactose oxidase after desialylation,189 but there is no evidence that it is the fucopyranosyl residues that are the specific receptors in these instances. The L-fucose-specific lectins from, for example, Lotus tetragonolobus and Ulex europeus are not mitogenic. 

The glycoproteins (ricin) are poorly absorbed from the gastrointestinal tract however, once absorbed, they most likely follow a distribution pattern similar to that of albumin. Many cell surfaces contain receptors specific for the ricin molecules. This molecule consists of two subunits, A and B, bound by a disulfide link. When this link is broken, the B subunit binds to galactose-containing receptors in the cell wall and is transported intracellularly. The A subunit inhibits protein synthesis. The liver, spleen, adrenal cortex, and bone marrow are the primary sites of distribution. The biotransformation and elimination of toxalbumins are poorly understood. The elimination half-life in one patient was 2 days. The reported disappearance of ricin from the plasma is according to first-order kinetics when... 

In effect, several lectins including galactose-specific lectin [94] and DEC-205 receptor [95] on cell surfaces could potentially bind the saponin sugar residues to assure targeting. This same delivery mechanism would assure that the same APC receiving the antigen would receive a stimulatory signal from the adjuvant. 

Hepatocyte adhesion in GC-coated PS and PVLA-coated PS was found to be similar (94.7%) after 120 min incubation. Hepatocyte adhesion on the PVLA was facilitated by the galactose-specific interactions between asialoglycoprotein receptors (ASGR) of the hepatocytes and galactose residues of the PVLA... 

Ricin, a glycoprotein present in the seeds of Rici-nus communis consists of two subunits joined by a disulphide bond. The A chain subunit or effecto-mer enzymatically inactivates the 60S ribosomal subimit, thus inhibiting protein synthesis (Olsnes and PiHL 1972) and causing cell death. The B chain subunit or haptomer serves to bind the ricin molecules to the galactose containing receptors that are present on most eucaryotic cell membranes. Carbohydratebinding specificity of ricin is as follows (ViERBUCHEN 1991) ... 

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