Thermal stability of different preparation of NOX immobilized onto differently activated agarose surfaces. The preparation of different NOX insoluble derivatives was carried out according to that described in Methods. 8 U (at 65°C) of each NOX insoluble preparations were incubated in 50 mM sodium phosphate at pH 7 and 83°C. At such conditions, half-life time of soluble NOX can be quantified in less than 24 h, allowing thus to calculate the stabilization factors achieved by each immobilization protocol. Stabilization factor was defined as the ration between the half-life times of each immobilized derivative and the soluble preparation. NOX preparations studied here were; soluble (empty rhombus), immobilized onto IDA-Cu2+-ag (crosses), immobilized onto CNBr-ag (full triangles) or immobilized onto Gx-ag (full squares). In all cases the crosslinking percentage of agarose was 6% (agarose-6BCL). Results represents the mean (± SD) of three different experiments.