A survey of the essentials of the experimental evidence assembled
in systematic extended voltammetric studies of denatured
and native DNA is rpresented. Applying an advanced verision of
single triangle sveep voltammetry at the HMDE and by supporting
measurements with various other polarographic methods, :such as
phase sensitive a.c.-voltammetry, the adsrnrption parameters, the
sequence of i!ll!terfacial events as a function of adsorption time and
adso1rption potentia·l arid the kinetics of the electrode process have
been elucidated. While for pH~ 7 in adsorbed DNA the adenine
and cytosime moieties are immediately reducible in a totally irreversible
electrode reaction Y•ielding a strongly adsorbed compact
film of reduction products, they have to become accessible to
electron and proton transfer in adsorbed native DNA in a sequence
of prior deconformation steps involving opening and unwinding of
the double helix under the co.nstraint exerted by the adsorption
interactions and by the interfacial electric field. In a fundamental
biophysicochemical sense the results enable general conclusions on
the behaviour of DNA when it interacts with charged interfaces d.m
the living cell
