Lipid peroxidation (LPO) is an oxidative degradation of lipids. LPO causes loss of membrane fluidity, disrupting membrane integrity and functions which resulted reduction of cell’s antioxidant capacity. Moreover, accumulation of lipid peroxides often cause cell death which is the key downstream feature of ferroptosis.
Through literature study, it is evident that glutathione peroxidase (GPx) and reduced glutathione (GSH) play significant role to attenuate LPO level. Can anyone help me to understand –
1) How does GPx and GSH impact LPO level?
2) Is there any correlation between lipid peroxidation (LPO) and glutathione peroxidase (GPx) activity?
What are your suggestions? Thanks in advance!
LPO ( oxidation of unsaturated fatty acid) is induced by free radicals , reactive oxygen species ( ROS) generally, glutathione family serve as enzyme dependent anti oxidant in cell, which captures free radicals, when oxidants ( free radicals) level exceeds anti-oxidants, cells undergo in stress condition which we call oxidatave stress , so in general when we study effect of any toxin or xenobiotic which introduce ros in tissue or cell we find high level lpo and low level of reduced glutathione.
Very nice question,
Glutathione Peroxidase (GPx) reduce lipid peroxidation and membrane damage, therefore, it protects to plant from stress. Due to oxidative stress in plant cell generate ROS like H2O2. Glutathione Peroxidase (GPx) is an important intracellular enzyme that breakdown hydrogen peroxides (H2O2) to water; and lipid peroxides to their corresponding alcohols mainly in the mitochondria and sometimes in the cytosol. Most times, its activity depends on a micronutrient cofactor known as selenium. For this reason, GPX is often referred to as a selenocysteine peroxidase. The enzyme plays a more crucial role of inhibiting lipid peroxidation process and therefore protects cells from oxidative stress.
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you can see this paper, Article Lipid peroxidation in cell death
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Free radical generation especially in the mitochondria during the electron transport chain causes lipid peroxidation. There is an inverse relationship between the enzymatic and nonenzymatic cellular defense systems. When free radicals increase, the cellular defense systems are activated, and vice versa. The increased oxidative stress causes a depletion of antioxidant defense systems characterized by a reduction in the activities of Superoxide reductase (SOD), Glutathione Peroxidase (GPx) and an increased Lipid peroxidation measured as malondialdehyde (MDA) concentrations as increased Reactive Oxygen Species (ROS) productions leads to the destruction of micro-/macro-molecular structures. GPx decomposes H2O2 to molecular oxygen and water using glutathione (GSH) as a co-factor. GSH is converted to the oxidised form GSSG which takes hydrogen ions from NADPH to regenerate GSH. So if LPO is increased, there is a depletion of the antioxidants.
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