BINDING OF BETA-2-GLYCOPROTEIN-I TO INTRALIPID - DETERMINATION OF THE DISSOCIATION-CONSTANT

Among the various proteins and apolipoproteins known to bind to Intralipid, an artificial triglyceride emulsion, we found also a specific uptake of β2-glycoprotein-I. The interaction occurs very fast; an equilibrium is reached after five minutes at 37°C. β2-glycoprotein-I which is present in fasting sera primarily in the density 1.23 g/ml bottom fraction, binds to Intralipid with a dissociation constant of approximately 10-8 moles/1. This value is higher than that reported for various apolipoproteins and model lipids. Neutral salts interact with this lipid binding glycoprotein in an uncompetitive type of reaction. Together with some other observations we believe that β2-glycoprotein-I may be of importance in triglyceride metabolism. © 1979.