Peroxidation cellular biomolecules

Fullerene showed antibacterial activity, which can be attributed to different interactions of C60 with biomolecules (Da Ros et al., 1996). In fact, there is a possibility to induce cell membrane disruption. The fullerene sphere seems not really adaptable to planar cellular surface, but for sure the hydrophobic surface can easily interact with membrane lipids and intercalate into them. However, it has been demonstrated that fullerene derivatives can inhibit bacterial growth by unpairing the respiratory chain. There is, first, a decrease of oxygen uptake at low fullerene derivative concentration, and then an increase of oxygen uptake, which is followed by an enhancement of hydrogen peroxide production. The higher concentration of C60 seems to produce an electron leak from the bacterial respiratory chain (Mashino et al., 2003). 

These radical species, along with others produced from their subsequent reactions, can react with biomolecules, such as proteins and DNA. The most damaging such reaction is lipid peroxidation, a process that involves the attack of chemically active species on unsaturated lipid molecules, followed by oxidation of the lipids through a free radical mechanism. It occurs in the liver and is a main mode of action of some hepatotoxicants, which can result in major cellular damage. The mechanism of lipid peroxidation may involve abstraction of the methylene hydrogens attached to doubly bonded carbon atoms in lipid molecules ... 

This reaction generates reactive hydroxyl radicals that can damage biomolecules. However, cellular hydrogen peroxide is rapidly removed by catalase and concentrations are very low, usually in the submicromolar concentration range. A Fenton-type reaction may therefore not be the primary cause of copper toxicity (Kaim and Rail, 1996). An alternative route of copper-induced cell damage is the depletion of sulfhydryls by redox cychng as described in reactions (2) and (3) ... 

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