Submaxillary mucin biosynthesis

Essentially similar results have been obtained by Eylar and co-workers " on the biosynthesis of bovine submaxillary mucin. The enzyme is firmly bound to a membrane solubilization by Triton X-100 results in a large increase in enzymic activity." The enzyme was purified by gel filtration, and its properties were studied. Among various substances studied, the only one (besides carbohydrate-free mucins) that was active as the acceptor of 2-acetamido-2-deoxy-D-galactose was a basic protein, called encephalitogen, isolated from bovine, spinal-cord myelin. ... 

Babczinski, P. (1980) Evidence against the Participation of Lipid Intermediates in in vitro Biosynthesis of Serine (Threonine)-iV-acetyl-D-galactosamine Linkages in Submaxillary Mucin FEBS Letters, 117, 207-11... 

McGuire, E.J. (1970) Biosynthesis of Submaxillary Mucins , in Blood and Tissue Antigens (D. Aminoff, ed). Academic Press, New York, pp. 461-78 McGuire, E.J. Roseman, S. (1967) Enzymatic Synthesis of the Protein-hexosamine Linkage in Sheep Submaxillary Mucin , Journal of Biological Chemistry, 242, 3745-55 Maestri, N. De Luca, L. (1973) Mannose Transfer from Mannolipid to Endogenous... 

Present knowledge on the biosynthesis of the prosthetic groups of OSM and porcine submaxillary mucin (PSM) is summarized in Fig. 12. Five glycosyltransferases are required for the synthesis of the most complex oligosaccharide side chain, the pentasaccharide present in PSM with human blood group A specificity (Carlson, 196, Section II). Four of these five enzymes are required for the synthesis of the side chain of blood group A-negative PSM two transferases are required for incorporation of the disaccharide side chain of OSM. 

FIGURE 10. The alternative pathways for mucin biosynthesis. Sialic acid addition prevents further sugar additions. Wavy line represents polypeptide backbone of submaxillary mucin. 

McGuire, E. J., 1970, Biosynthesis of submaxillary mucins, in Blood and Tissue Antigens (David Aminoff, ed.), pp. 461-478, Academic Press, New York. 

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