Quantitative determination of surface concentration of human apolipoprotein H with capillary electrophoresis

The phospholipid monolayer at an air/water interface is widely used to mimi c the biological membrane. The dynamic process of the protein or peptide in teracting with lipid molecules can be reflected in the change in surface pr essure of the monolayer, But the conventional method used to measure the su rface pressure change gives results that cannot easily be correlated with t he contribution of a single protein molecule. Previously, measuring the sur face concentration of the protein molecules at the air/water interface has required the protein to be labeled with radioactivity or fluorescence. Here , a new method using capillary electrophoresis is introduced to measure the surface concentration of the protein, The results show at least two advant ages of the new method: The numerical results of protein concentration can be obtained in a more precise and rapid way; and there is no need to label the protein sample or to build a special monolayer setup.