Application of dye-ligand chromatography to the isolation of α-1-proteinase inhibitor and α-1-acid glycoprotein

Various Cibacron blue F3G-A substituted Sephadex G-100 gels which differ in the density of the bound dye were investigated for their applicability in the affinity chromatography of human serum proteins. Protein adsorption was found to depend strongly on the density of the covalently attached dye and on the pH of the applied buffer. A high degree of dye substitution of the gel caused binding of most of the serum proteins. Only a small number of proteins were found to appear in the breakthrough fraction. On this basis a simple and relatively mild procedure for the isolation of homogenous α-1-proteinase inhibitor and α-1-acid glycoprotein from human serum was developed. Isolation of α-1-acid glycoprotein succeeded in only a single step, whereas that of α-1-proteinase inhibitor required two additional steps: a prior ammonium sulphate precipitation and a chromatographic step on DEAE-cellulose at pH 6.5.