A Method for distinguishing between α- and β-Glycosides by the use of Plant Hæmagglutinins (Lectins)

Abstract

SEVERAL plant seeds contain proteins that agglutinate red blood cells^1,2 as do many antibodies. For these proteins the name ‘lectins’ has been suggested³. They can be as specific as animal antibodies in that they react only with erythrocytes of certain blood groups. The ABO blood group specific lectins—as well as the ABO specific antibodies—are inhibited by some simple sugars, mainly components of blood group polysaccharides^1,2,4. Several ‘unspecific’ lectins are also inhibited by simple sugars, but these sugars are not necessarily components of blood group polysaccharides^1,2. The explanation of this phenomenon is that the sugars, the structure of which most closely resembles the specific (sugar) group of the red cell receptor, attach themselves to the active site(s) of the lectin molecule, thus blocking them.