Control of the electron transfer reactions between c-type cytochromes and lipid-modified electrodes

✍ Scribed by Pierre Bianco; Jean Haladjian

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 607 KB
• Volume: 39
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(94)85105-0

✦ Synopsis

The electron transfer reactions between a lipid-modified pyrolytic graphite (PG) electrode and four c-type cytochromes (monoheme cytochrome c and cytochrome cSsJ from Desulfooibrio uulgaris Hildenborough, tetraheme cytochromes cj from D. uulgaris Hildenborough and D. desuljkicans Norway) have been studied by cyclic and square-wave voltammetry. No signal was detected at the PG electrode simply coated with a mixed layer of phosphatidylcholine (PC) and cholesterol (CH). The peaks corresponding to the reduction-reoxidation of cytochrome c,~~ were restored by doping the lipid layer with laurate anions (LA). In the case of cytochrome c, a rapid electron transfer reaction has been observed at the (PC-CH + LA)-modified PG electrode, accompanied by the progressive incorporation of protein molecules.

By studying the effect of pH on the co peak heights, it has ken shown that the profiles for the four cytochromes depend on the protonation of the laurate anions and the protonation-deprotonation of protein species.

The results support the electrostatic nature of the interactions between the cytochrome and the lipid layer but other factors (eg hydrophobic effects) are not excluded.