Phospho-l-tyrosine-agarose chromatography: adsorption of human IgG and its proteolytic fragments

The behavior of human immunoglobulin G (IgG) and antigen-binding fragment (Fab fragment) adsorption onto phospho-l-tyrosine immobilized on agarose (P-Tyr-agarose) was evaluated by pseudoaffinity chromatography. The effects of buffer systems MES, MOPS, Bis-Tris, Tris-HCl and sodium phosphate (NaP) and pH on IgG adsorption were studied and high purity values were obtained (96%, based on ELISA analysis of albumin, transferrin and immunoglobulins A, G and M) when IgG was purified from human plasma diluted in 10 mmol L-1 NaP buffer at pH 6.0. The capture of IgG by the P-Tyr-agarose was also promising, since 91% of the IgG was adsorbed when plasma was diluted in 25 mmol L-1 MES buffer at pH 5.5, recommending its use for IgG depletion from human plasma under this condition. The experimental data on IgG adsorption kinetics were in agreement with the pseudo-second-order model. The adsorption isotherm data were well described by the Langmuir-Freundlich model with the value of parameter n being