Dynamics of carbohydrate-lectin interaction. The interaction p-nitrophenyl-beta-D-galactose with a lectin from Ricinius communis.

L&in-induced agglutination is a complex process determined by several factprs such as the nature of lectin (valency, binding constant) the properties of cell membrane (fluidity, distribution of lectin receptor sites) and the metabolic state of the cell (microvilli, microtubules, microfilament) [l-3] . In order to assess quantitatively the effect of each of these factors, one has to obtain the thermodynamic and kinetic parameters of the interaction of various lectins with simple sugars, glycolipids and glycoproteins. We have been trying to estimate these parameters, particularly from the kinetic analysis of the precipitin reaction of the glycoprotein-lectin and glycolipidlectin systems in aqueous and lipid phases [4,5]. Here we wish to report our T-jump relaxation kinetic study on the binding of p-nitrophenyl-P-D-galactose (NPG) to RCAl, a galactose specific lectin isolated from Ricinius communis beans and the turbidimetric data on the binding of galactomanan to RCA1 . It is also shown that the presence of a small amount of galactose or its derivatives decreases the initial rate of the precipitin reaction. The relevance of this finding to lectin receptor binding assay is also disscussed.