Biosensors with enzymes other than SODs

1 Biosensors with enzymes other than SODs 

In addition to a family of SODs, several other kinds of enzymes and proteins, including tyrosinase [87], galactose oxidase [87], hemin, and cytochrome c (Cyt. c), have been employed to construct enzyme-based biosensors for the O2 determination. Here, we will use Cyt. c as an example to illustrate the analytical mechanism of such a kind of 02 biosensors. For constructing a Cyt. c-based biosensor, Cyt. c is normally inunobilized on the electrode surface and acts as an electron transfer mediator between the electrode and 02. The O2 radical reduces the immobilized Cyt. c (Fe(lll)) to Cyt. c (Fe(II)) and the Cyt. c (Fe(ll)) is reoxidized on the electrode at a potential of 

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