response to hydrogen peroxide

Definition

Target type: biologicalprocess

Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a hydrogen peroxide (H2O2) stimulus. [GOC:jl]

Response to hydrogen peroxide is a complex cellular process involving a cascade of signaling events that are initiated by the generation of reactive oxygen species (ROS), such as hydrogen peroxide (H2O2). H2O2 is a potent oxidant that can damage cellular components, including DNA, proteins, and lipids. To mitigate this damage, cells have evolved intricate mechanisms to detect and neutralize H2O2.

The first step in the response to H2O2 is its detection by various sensors, including redox-sensitive proteins and enzymes. These sensors, upon encountering H2O2, undergo conformational changes that trigger downstream signaling pathways. Key players in this detection process include the following:

- **Peroxiredoxin (Prx) family:** These enzymes are highly efficient H2O2 scavengers and act as redox sensors. Their oxidation by H2O2 leads to the activation of downstream signaling pathways.
- **Catalase:** Another important enzyme that detoxifies H2O2 by converting it to water and oxygen.
- **Glutathione peroxidase (GPx):** This enzyme reduces H2O2 using glutathione as a reducing agent.

Once H2O2 is detected, cells activate a multitude of signaling pathways to mount a comprehensive response. These pathways involve various signaling molecules, including:

- **Mitogen-activated protein kinases (MAPKs):** These kinases play a central role in mediating stress responses, including the response to H2O2. Activation of MAPKs, such as JNK and p38, triggers downstream signaling events leading to changes in gene expression and cellular processes.
- **Nuclear factor erythroid 2-related factor 2 (Nrf2):** This transcription factor plays a key role in the induction of antioxidant genes. Upon activation by H2O2, Nrf2 translocates to the nucleus and activates the transcription of genes involved in detoxification and antioxidant defense.
- **Transcription factor activator protein 1 (AP-1):** This transcription factor is involved in regulating the expression of genes related to inflammation and cell death. Its activation by H2O2 contributes to the cellular response to oxidative stress.

These signaling pathways ultimately lead to the activation of various cellular processes aimed at restoring homeostasis and mitigating damage caused by H2O2:

- **Antioxidant defense:** Cells increase the production of antioxidant enzymes, such as catalase, GPx, and superoxide dismutase (SOD), to neutralize ROS and protect cellular components.
- **DNA repair:** Cells activate DNA repair pathways to repair damage caused by H2O2 to DNA.
- **Protein repair:** Cells engage in protein repair mechanisms to restore the functionality of proteins damaged by oxidation.
- **Apoptosis:** In severe cases of oxidative stress, cells may undergo programmed cell death (apoptosis) to eliminate damaged cells and prevent further damage to the organism.

The response to H2O2 is highly dynamic and involves a complex interplay of signaling pathways and cellular processes. The outcome of this response depends on factors such as the concentration of H2O2, the duration of exposure, and the cellular context. While H2O2 can be detrimental at high concentrations, at low levels, it can act as a signaling molecule, triggering adaptive responses that promote cell survival and enhance resistance to oxidative stress.'
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Proteins (16)

Compounds (451)