ELECTROPHORETIC BEHAVIOR OF ANTIGEN-CARRYING AND ANTIBODY-CARRYING LATEX-PARTICLES

Electrophoretic mobilities of antigen (human serum albumin, HSA)- and antibody (anti-HSA immunoglobulin G, IgG)-carrying latex particles were measured at different pH and ionic strengths. Carboxylated latex particles were used, and the proteins were fixed on the latex particle surface by chemical bonding. The results were analyzed by a mobility formula which directly relates the measured electrophoretic mobility with the charge density in the surface region of protein-carrying latex particles. It was shown that the value of d, which is the thickness of the protein layer bound on the surface of latex particles in our formula, reflects the size of each protein; namely, the values of d obtained in the best fitting were 100 Å for the IgG and 60 Å for the HSA bound to latex, respectively. © 1992.