Visual Assessment of Enzyme Immobilization

Immobilization of enzymes is a basic technique that is well established in very different fields of both research and industry. The actual knowledge of the basic principles for immobilizing enzymes is so broad that one can design the immobilized enzyme to accomplish a given task or to show properties that are the most suitable for a given application (1 ,2 ). However, for most circumstances, the success or failure of an immobilization process can only be checked once the immobilization process is complete, because the physical appearance of the support material does not change during the immobilization process. Thus, it is very difficult (unless appropriate chemical or physicochemical methods are used at every intermediate step) to know if the support has been adequately activated, the spacer arm was successfully attached to the support, or the protein was bound to the spacer arm. Therefore, a method for enzyme immobilization in which the different steps of the process can be assessed by changes in color of the derivatives would be a useful check, in the first instance, of the success or failure of the immobilization procedure (3 ).