Oxidation-reduction (i.e. redox) processes at the plasma membrane of any
cell have been attracting more and more attention, both in basic and in
applied research, since the first workshop dealing with the plasma
membrane oxidoreductases was organized in Cordoba, Spain, in 1988. This
evolution is evident considering the numerous cell functions performed
by plasma membrane redox systems not only in healthy cells but also in
cells that escaped from the normal metabolic control (e.g. cancer cells)
and cells under attack by pathogens. Plasma membrane redox processes
have now been demonstrated to play an essential role in growth control
and defense mechanisms of these cells. The great importance of the
plasma membrane redox systems originates in the fact that they are
located in the membrane which is essentially the site of communication
between the living cell and its environment. We may say that the plasma
membrane can be considered as the "sensory part" of the cell. No
chemical substance can enter the cell interior without interaction with
the plasma membrane.