Protection of protein A-sepharose columns irradiated to sterilization doses

Abstract The effects of ionizing radiation on protein A-sepharose mini columns have been investigated. Radiolysis to a dose of 25 kGy is accompanied by a 55% loss of binding capacity to IgG. Various OH . radical scavengers have been used to render them radiation resistant at the high doses commonly used for the purpose of sterilization. Inclusion of mannitol at high concentrations (1 mol dm −3 ) partially protects the columns as does ascorbate (10 −2 mol dm −3 ), the loss of binding being only ∼15% at 25 kGy. A mixture of mannitol (1 mol dm −3 ) and ascorbate (10 −2 mol dm −3 ) however protects to ∼5% decomposition. This value is not effected by the presence of oxygen at the beginning of irradiation.