Organic electronic element from modified cytochrome c551 and cytochrome c552

An electronic element comprising:

• an electrode and a monomolecular film, wherein
• said film is absorbed to said electrode and comprises a modified protein,
• said modified protein comprising a cytochrome which has a first electron transfer functional group having a first redox potential, wherein said cytochrome has been modified by covalently bonding a second electron transfer functional group which has a second redox potential to an amino acid residue of said cytochrome, selected from the group consisting of Lys 76 modified to Cys 76 and Trp 77 modified to Cys 77 said second electron transfer group being located so as to allow electron transfer between said first and second electron transfer functional groups, wherein said cytochrome is cytochrome c551, and
• wherein said redox potential of said first electron transfer functional group is different from said redox potential of said second electron transfer functional group.