Application of cellulosic fast‐flow column filters to protein immobilisation and recovery

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Abstract
The suitability of a new paper‐like cellulosic rod as a support for the immobilisation of proteins has been studied as an alternative to the common, beaded supports. α‐Amylase was covalently immobilised on to this paper‐like cellulosic support using cyanogen bromide and 1,1′‐carbonyldiimidazole activation procedures. The enzymic activity of α‐amylase immobilised onto the activated support was measured by the initial rate of hydrolysis of starch. During the first three successive assays 60‐70% of the initial activity of the immobilised α‐amylase was lost (possibly due to non‐specific adsorption of the protein), then becoming stable. This enzymic activity was retained after long storage periods. The amounts of enzyme bound to cyanogen bromide and 1,1′‐carbonyldiimidazole‐activated supports, calculated from the specific catalytic activity of α‐amylase, were 0.52 and 0.59μgg−1 respectively. Proteins A and G were also coupled to the cellulosic support using 1,1′‐carbonyldiimidazole. The amounts of proteins A and G bound to the activated support, determined spectrophotometrically at 260 and 280nm, were 2.33 and 0.31 mg g−1, respectively. The binding between various radiolabelled immunoglobulins of the G class and immobilised proteins A and G were examined. The IgG binding profiles of immunophilic proteins coupled to paper‐like cellulosic rod and to commercially available beaded supports were similar. Therefore, this paper‐like cellulosic support is a potential matrix for bioseparators, bioreactors and affinity chromatography.