Electro-Enzymatic Studies of the Interfacial Behaviour of Proteins

Biospecific electrodes for the determination of nine metabolites and for six enzyme activities have been brought into the clinical laboratory by our group1. These sensors contain a dialysis membrane and up to three sequentially acting enzymes. Worldwide commercial enzyme electrodes use the membrane technique which was adapted from the Clarktype oxygen electrode. More direct enzyme fixation is needed for affinity and immunosensors and enzyme FETs. In addition to the covalent binding at the electrode surface, adsorption of the protein also offers several advantages, i.e., simple enzyme loading and low diffusion resistance. In addition to analytical applications the adsorption of protein at interfaces is also of fundamental interest and plays an important role in other biotechnological processes such as chromatography or immobilization on solid carriers.