Serum glycoproteins in the liver diseases. I. Studies on sialic acid-free glycoproteins-improved competitive binding assay of desialylated glycoprotein by rat liver plasma membrane.

An improved method for quantitation of desialylated glycoproteins was developed. The assay was carried out in non-saturating condition other than saturating condition which has been used by the other authors. In the present method a lower radioactivity in the assay solution can be used. Standard curves obtained by adding an increasing amount of desialylated alpha1-acid glycoprotein to the assay solution made it possible to measure desialylated glycoproteins equivalent to 5-200 ng of desialylated alpha1-acid glycoprotein. Desialylated alpha1-acid glycoprotein used for the assay could be prepared in large scale by hydrolysis with 0.1 N-H2SO4.