Comparison of binding sites for wheat germ agglutinin on Raji lymphoblastoid cells and their isolated nuclei and plasma membranes.
Raji lymphoblastoid cells and the cell nuclei and plasma membranes isolated by the glycerol-lysis technique [Jett, M., Seed, T., & Jamieson, G. A. (1977) J. Biol. Chem. 252, 2134-2142] have been examined for their ability to bind wheat germ agglutinin. Intact cells and isolated nuclei showed similarities (i) in the total number of binding sites (3.38 X 10(6) and 4.06 X 10(8), respectively), indicating at least a 2-fold higher receptor density on the nuclei, (ii) in the ratios of the number of high-affinity sites and low-affinity sites (1.05 and 1.07), and (iii) in the apparent association constants at the high-affinity sites (28 nM and 48 nM) and at the low-affinity site (116 nM and 370 nM). Isolated plasma membranes had a similar number of total binding sites calculated on an equivalent cell basis (2.01 X 10(6)) but showed differences in the ratio of high- to low-affinity sites (1.5) and in their apparent association constants (3 nM and 22 nM). These results suggest similarities in the lectin receptors on the outer surface of lymphoblastoid cells and the cell nuclei. The differences obtained with isolated membranes may be due to inversion of the membrane vesicles or to their decreased rigidity as compared with the intact cell.
D002462:Cell Membrane / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D007700:Kinetics; D008214:Lymphocytes / Q000378:metabolism*; D011975:Receptors, Mitogen / Q000378:metabolism*
D011975:Receptors, Mitogen; C027503:wheat germ agglutinin receptor