PLANT AGGLUTININS (LECTINS) II 



n 



Lotus tctragouolobits and Ulex curopeus. L-Fucose does not inhibit 

 the anti-H of Cyfisits sessilifolius or of Laburnum alpinum, but salicin, 

 a gkicoside of D-glucose and sahgenin, does (Bird, 1959). If this 

 means that the lectins of Cytisus and Laburnum are directed toward 

 a part of the H antigen different from that recognized by the animal 

 anti-H reagents, it might suggest that the specificity of the lectins 

 is greater, not less than that of the animal agglutinins. 



The anti-H of Lotus tctragonolohus is inhibited also by 2-deoxy- 

 L-fucose, L-galactose, 6-deoxy-L-talose, D-arabinose, and vV-acetyl- 

 glucosamine. Morgan and Watkins (1953) pointed out that, except 

 for the last, all the inhibiting sugars, when written in the pyranose 

 form, have the same configuration at carbon atoms 3 and 4 (Fig. 6-2) . 

 In all of them the hydroxyl groups are on the same side of the pyran 

 ring and pointing down. 



Kriipe (1956) noticed that the sugars which inhibited the anti- 

 (A-|-B) agglutinin of Sopliora japonica (A^-acetyl-D-galactosamine, 



H.OH 



OH 

 6-Deoxy-L-talose 



H.OH 



H.OH 



HO 



^6h 



H.GH 



D-Digitoxose 

 Fig. 6-2. Haworth formulas of sugars inhibiting anti-H of Lotus tctra- 

 gonolohus. Arrows point to carbons 3 and 4, which liave the same configuration 

 in all these substances. (Redrawn from Morgan and Watkins, 1953). 



