proton transmembrane transport

Definition

Target type: biologicalprocess

The directed movement of a proton across a membrane. [GO_REF:0000069, GOC:pr, GOC:TermGenie]

Proton transmembrane transport is a fundamental process in biology, crucial for maintaining cellular pH, generating ATP, and powering various metabolic reactions. This transport involves the movement of protons (H+) across cellular membranes, driven by electrochemical gradients or active transport mechanisms.

**Electrochemical Gradient-Driven Transport:**

- **Passive diffusion:** Protons can move down their concentration gradient through specific proton channels embedded in the membrane. These channels are often gated and regulated, allowing for controlled proton flux.
- **Facilitated diffusion:** Proton carriers, such as the proton-coupled symporters and antiporters, utilize the energy stored in the electrochemical gradient of other ions to move protons across the membrane. For example, a proton-sodium antiporter uses the inward gradient of sodium ions to drive the outward movement of protons.

**Active Transport:**

- **Proton pumps:** These membrane-bound proteins utilize energy sources like ATP hydrolysis or light energy to actively move protons against their concentration gradient. This creates a proton gradient across the membrane, storing potential energy.
- **Proton-translocating ATPases:** These specialized pumps utilize the energy from ATP hydrolysis to pump protons across the membrane, generating a proton motive force. This force is used to power other cellular processes, such as ATP synthesis.

**Biological Significance:**

- **Cellular pH regulation:** Proton transport is essential for maintaining the pH balance within cells, which is crucial for enzyme activity and overall cellular function.
- **ATP synthesis:** Proton pumps and proton-translocating ATPases are crucial components of oxidative phosphorylation, the primary pathway for ATP production in eukaryotic cells.
- **Metabolic processes:** Proton gradients are used to power various metabolic reactions, such as nutrient uptake, waste excretion, and signal transduction.
- **Organelle function:** Proton transport plays a role in the function of specific organelles, such as mitochondria, lysosomes, and vacuoles.

**Examples:**

- **Mitochondrial electron transport chain:** Protons are pumped across the mitochondrial inner membrane by electron carriers, generating a proton gradient that drives ATP synthesis.
- **Gastric acid secretion:** Proton pumps in parietal cells of the stomach actively pump protons into the stomach lumen, generating gastric acid.
- **Plant photosynthesis:** Light-driven proton pumps in chloroplasts generate a proton gradient that powers ATP synthesis and drives carbon fixation.

Proton transmembrane transport is a highly regulated and complex process that is essential for the survival and function of all living organisms.'
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Proteins (39)

Compounds (515)