The dietary
lectins, edible mushroom (ABL) and
Jacalin (JAC) inhibit the proliferation of
colonic cancer cells, whereas Amaranth (ACL) and peanut (PNA) stimulate their proliferation. All these
lectins share as their preferred
ligand the Thomsen-Friedenreich (
TF) antigen galactosyl beta1,3 N-
Acetylgalactosamine (Galbeta1,3GalNAc), but differ in their finer specificities for modifications of this determinant and in their specificities for cancerous epithelia. We have investigated, using a resonant mirror biosensor, the kinetics of binding of these
lectins, and
Maclura pomifera lectin (MPL), which is similar to JAC, to two different
Gal-GalNac bearing
glycoproteins, antarctic fish
antifreeze glycoprotein (AFG) and
asialofetuin. JAC had the highest affinity for AFG [K(d) 0.027 microM] due to a fast association rate constant [k(ass) 610,000 (Ms)(-1)]. The other
lectins had considerably lower affinities, with K(d) ranging from 0.16 microM (ABL) to 5.7 microM (PNA), largely due to slower k(ass) [ABL 74,000 (Ms)(-1) to PNA 2700 (Ms)(-1)]. Similarly, JAC had a much higher affinity for
asialofetuin [K(d) 0.083 microM] than the other
lectins [K(d) 1.0 microM-4.5 microM]. Affinities were also calculated from the extent of binding at equlibrium and were generally similar to those calculated from the kinetic parameters indicating the true nature of these values.