Electron-Transfer Properties of Cytochrome c Langmuir−Blodgett Films and Interactions of Cytochrome c with Lipids

Abstract

The structural and electron-transfer properties of cytochrome c (Cyt c) Langmuir−Blodgett (LB) films have been studied on graphite electrode with tapping mode atomic force microscopy and cyclic voltammetry (CV). Cyt c in the LB films forms an ordered monolayer in which the individual proteins pack into a quasi-hexagonal structure. The monolayer undergoes a reversible electron-transfer reaction in phosphate buffer. The interactions of Cyt c with cardiolipin (CL) and phosphatidylcholine (PC) LB films have been studied. The LB films of CL and PC are both ordered on graphite, but their interactions with Cyt c are quite different. On a CL monolayer, Cyt c adsorbs spontaneously and the adsorbed protein preserves the electron-transfer reaction. However, on a PC monolayer, Cyt c does not adsorb.

Electrochemical Response of a Vitreous Carbon Electrode Modified by a Thiomacrocyclic Compound Film

“…In the experiments with the vitreous carbon rod electrode modified with a LS film of thiomacrocycle bonded to Cu 2+ (Cu 2+ -ThM), the electrochemical cell contained 0.1 M Na 2 SO 4 at the pH of the salt (4.95). In the other experiments the electrochemical cell contained 0.1 M Na 2 SO 4 as the supporting electrolyte and aliquots of CuSO 4 were pipetted into the cell from a 0.5 M CuSO 4 solution. The total Cu 2+ ion bulk concentration in solution, c Cu , was varied from 0.01 mM to 10 mM.…”

“…The LB technique can create monolayer and multilayer structures with large-scale order and this technique has been used to fabricate modified electrodes at the nanometric scale [3], with potential applications in sensors and optical and electronic devices. The LB technique can also provide new insight into electron transfer reactions at interfaces [4][5][6][7][8][9]. The LS technique, i.e.…”

Composite Magnetic Particles as Carriers for Laccase from Trametes versicolor

“…[1][2][3][4] Biomolecules such as proteins have been immobilised on various supports, such as phospholipids bilayers, [5] self-assembled monolayers, [6,7] Langmuir-Blodgett films, [8,9] polymer matrices [10,11] and galleries of a-zirconiumphosphate, [12,13] as well as in thermally evaporated fatty lipid films. [14][15][16][17][18][19] The use of nano-or submicroparticles, with their extremely high surface-to-volume ratio, in the immobilisation of biomolecules dates back to the early 1980s.…”

Immobilization and biocatalytic activity of fungal protease on gold nanoparticle‐loaded zeolite microspheres

“…Insofar as enzymes are concerned, advantages of immobilized enzymes over their counterparts in solution include enhanced temperature and temporal stability of the biocatalyst and ease of separation from the reaction medium, enabling multiple reuses. A number of templates have been used for enzyme immobilization, such as silica nanotubes (Mitchell et al, 2002), phospholipid bilayers (Chen et al, 1999;Hamachi et al, 1994), self-assembled monolayers (Fang et al, 1996;Mrksich et al, 1995), Langmuir -Blodgett films (Boussaand et al, 1998;Nicolini et al, 1993), polymer matrices (Franchina et al, 1999;Yang et al, 1995), galleries of a-zirconium phosphate (Kumar and McLendon, 1997), mesoporous silicates such as MCM-41 (He et al, 2000), silica nanoparticles (Qhobosheane et al, 2001), and thermally evaporated lipid films (Sastry, 2002;Sastry et al, 2002), each with its characteristic advantages and disadvantages.…”