Dissociation and Association Rate Constants Changes following Bilirubin Binding Affinity Decreases

The effect of sulfisoxazole, sodium salicylate, sodium cholate, urea and dimethyl sulfoxide on the kinetics of the bilirubin to human serum albumin at 24 degrees C and pH 7.40 was investigated. A marked decrease of the association constant was obtained. It was due mainly to that of the association rate constant, and might be an additional risk factor to the icteric newborn: when blood bilirubin increases, unbound bilirubin which cannot rapidly associate to albumin may reach a dangerous level, even when its equilibrium concentration is low.