Acetamido-2-deoxy-D-galactose-binding Lectins

From agar-gel diffusion and precipitin studies of ovarian cyst Ai and A2 substances with Dolichos extract, Bird10,178 concluded that the lectin made no qualitative distinction between the two subgroups of A. Hog gastric-mucin A substance reacted in a manner identical to the cyst substances. 

Etzler and Kabat purified the agglutinating principle from Dolichos seed extracts by adsorption to insoluble polyleucyl hog A + H substance.108,517 Specific elution of the adsorbent with 2-acetamido-2-deoxy-D-galactose gave a protein that appeared homogeneous by immunodiffusion, immunoelectrophoresis, disc-gel electrophoresis under acid and alkaline conditions, and sedimentation analysis. The amino acid composition of the protein of molecular weight 141,000 reflected a high content of aspartic acid and serine, little methionine, and no cysteine. Carbohydrate analysis showed a sugar content of 2.4% of hexose, 1.6% of hexosamine, and 1.5% of 2-acetamido-2-deoxy-hexose. 

An alternative purification of Dolichos biflorus lectin was published by Font and coworkers.518 Fractional precipitation with ammonium 

The carbohydrate-binding specificity of purified Dolichos biflorus lectin has been studied in detail by Etzler and Kabat.108 In precipitin studies conducted on the Dolichos lectin, 87-99% was precipitated by ovarian cyst A substance, whereas only 60-70% was precipitated by hog A substance the latter result was attributed to the formation of soluble, lectin-oligosaccharide complexes. At substances were more reactive than A2 substances however, no reaction was observed with B or O substances, even following mild hydrolysis with acid or two stepwise, Smith degradations. N-Deacetylation of A substance with 

Clostridium tertium N-deacetylating enzyme abolished Dolichos lectin reactivity restoration was achieved by re-N-acetylation. 

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A comparative study of the carbohydrate-binding specificity of four 2-acetamido-2-deoxy-D-galactose-binding lectins (from Dolichos biflorus, Glycine max, Helix pomatia, and Phaseolus lunatus) has been conducted by using a series of model macromolecules for direct precipitation and a variety of mono- and oligo-saccharides as hapten inhibitors.592 The data indicated that the combining site of all four lectins... 

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