Immobilization of beta-galactosidase, albumin, and gamma-globulin on epoxy-activated acrylic beads

A comparative study was conducted into the immobilization of beta-galactosidase, albumin, and gamma-globulin on an epoxy-activated polyacrylic matrix (oxirane C, R?hm-Pharma GmbH, Darmstadt). The kinetic parameters of the immobilized beta-galactosidase were investigated with three kinds of miniaturized analytical reactors; namely, stirred batch, continuous stirred-tank, and packed-bed reactors. The optimum binding conditions, saturation activity and Michaelis constant of immobilized beta-galactosidase are given, together with determinations of the binding capacity of the oxirane C matrix for the three proteins investigated. For beta-galactosidase a saturation activity of 1300 U/g oxirane C was reached. The maximum binding, achieved by experiment, was 140 mg/g with 0.69 yield for albumin, 120 mg/g with 0.61 yield for gamma-globulin, and 40 mg/g with 0.42 yield for beta-galactosidase. From these data the inner surface of the matrix as a function of the size of the bound proteins was estimated.