Comparison of binding characteristics of factors B and H to C3b on normal and paroxysmal nocturnal hemoglobinuria erythrocytes.

摘要: To determine if aberrant interactions of the endogenous control proteins with cell-bound C3b contribute to greater fixation paroxysmal nocturnal hemoglobinuria (PNH) erythrocytes when whole serum complement is activated, we compared characteristics binding factors B and H normal PNH red cells bearing (EC3b). Factor homogeneous, there 1:1 stoichiometry, affinity constant at equilibrium for factor same EC3b. In contrast, analysis by Scatchard's method results in a curvilinear plot, deviation from linearity being exaggerated The heterogeneity appears be consequence nonrandom distribution about alternative pathway convertase site. This does not induce negative cooperativity but rather effects biophysical milieu which enhances binding. E nonrandomly distributed due presence proportion lower sites on However, it unlikely that this contributes enhanced erythrocytes.