Adsorption of Bovine Serum Albumin and γ-Globulin on Chitosan Membrane

Adsorption of proteins on chitosan, which has positively charged proups, was investigated. The amount of adsorption depended on pH values and showed the maximum at the isoelectric point of BSA (pH 4.5-5.0) as was recognized in non-charged polymer membl-anes. Also it depended on an ionic strength, which affected the maximum point as well as the amount itself. It was considered that the positive charge of chitosan may affect the isoelectric point of BSA at which the smallest lateral interaction appeared to make the compactest form of BSA molecule. Whereas, contrary to the general tendency observed at much lower concentration of BSA, the amount of maximum adsorption decreased as the ionic st.rength decreased. This suggests that at relatively high concentration, the reduction of shielding effect of ions may give the increase of repulsion between BSA molecules rather than that of interaction between BSA and chitosan molecules. The adsorption of γ-globulin was studied, too. Futhermore, the adsorption of chitosan onto a silk fiber as substitute for human hair was studied to result in the usefulness as the rinsing agent