Ha. Tsai et al., Influence of surface hydrophobic groups on the adsorption of proteins ontononporous polymeric particles with immobilized metal ions, J COLL I SC, 240(2), 2001, pp. 379-383
Iminodiacetic acid (IDA) and octyl moieties were covalently bound on nonpor
ous particles, which were prepared from dispersion polymerization of methyl
methacrylate and glycidyl methacrylate. After being charged with copper io
ns, the IDA-bound particles could specifically adsorb deoxyribonuclease I (
DNase I) through the affinity interaction between protein and immobilized m
etal ion. A mixed-ligand (metal-chelate and octyl-bound) support was obtain
ed after hydrophobic (octyl) groups were also introduced to the particle su
rface. The affinity adsorption of DNase I on the copper-IDA chelate was inf
luenced by interaction between the protein and the bound octyl group. Both
the affinity and the hydrophobic interactions could be well described by th
e Langmuir isotherms. The equilibrium adsorption constants were estimated s
eparately to be 0.96 and 0.50 liter g(-1) for affinity and hydrophobic bind
ings, respectively. For binding on mixed-ligand support, the adsorption con
stant was 0.45 liter g(-1). It was evident that both affinity and hydrophob
ic interactions are involved in the adsorption of proteins onto mixed-ligan
d particles. Desorption of the inactive proteins from the support was possi
ble by increasing the hydrophobicity of the solution. (C) 2001 Academic Pre
ss.