intracellular pH reduction

Definition

Target type: biologicalprocess

Any process that reduces the internal pH of a cell, measured by the concentration of the hydrogen ion. [GOC:ai]

Intracellular pH reduction is a complex biological process that involves the movement of protons (H+) across cellular membranes. It is crucial for maintaining cellular homeostasis and is involved in various physiological functions, including:

- **Regulation of enzyme activity:** Many enzymes have optimal pH ranges, and pH changes can alter their activity.
- **Signal transduction:** pH changes can act as signaling molecules, triggering downstream pathways.
- **Protein folding and stability:** pH influences the folding and stability of proteins, which can impact their function.
- **Cellular metabolism:** pH gradients are critical for driving various metabolic reactions, such as ATP production.

**Mechanisms of intracellular pH reduction:**

- **Proton pumps:** These transmembrane proteins actively transport protons out of the cell, lowering intracellular pH. Examples include the Na+/H+ exchanger (NHE) and the vacuolar H+-ATPase (V-ATPase).
- **Carbon dioxide (CO2) production:** Metabolic processes such as glycolysis and oxidative phosphorylation generate CO2, which can be converted to carbonic acid (H2CO3) and then to bicarbonate (HCO3-) and protons.
- **Metabolic acid production:** Metabolic pathways, like anaerobic glycolysis, produce organic acids (e.g., lactic acid) that contribute to acidification.
- **Leakage of protons:** Imperfections in the cell membrane can lead to leakage of protons into the cell.

**Regulation of intracellular pH:**

- **Buffering systems:** Cells contain buffering systems, such as proteins and bicarbonate, that help to resist changes in pH.
- **pH sensors:** Cells possess sensors that detect pH changes and activate signaling pathways to restore pH homeostasis.
- **Compensation mechanisms:** If pH drops too low, cells can activate mechanisms to increase pH, such as increasing proton extrusion or reducing acid production.

**Disruption of intracellular pH homeostasis:**

- **Metabolic disorders:** Conditions like diabetes and lactic acidosis can disrupt pH balance.
- **Cellular stress:** Exposure to toxins, hypoxia, and other stressors can lead to pH changes.
- **Disease states:** Cancer cells often exhibit altered pH regulation.

**Conclusion:**

Intracellular pH reduction is a vital process that is tightly regulated to maintain cellular function. Its disruption can have severe consequences for cell health and disease development.'
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Proteins (2)

Compounds (2)