Electrocatalytic properties of catalase (CAT) immobilized on graphite and soot to mediate electrooxidation of phenol have been investigated. The kinetic parameters--Km, k(s), deltaG*Ar and Z0 of the process studied were calculated. Conclusions on a probable mechanism of the biocatalytic and electrochemical process observed were drawn from the calculated values of activation and kinetic parameters. A quantitative UV-spectrophotometrical approach was used as an analytical tool. The electrochemical oxidation of phenol was examined with potentiodynamic and polarization curves' method.