Extracellular and intracellular pH (pH) (pH)

Extracellular and intracellular pH (pH) refers to the concentration of hydrogen ions within cellular compartments and the surrounding interstitial fluid, serving as a fundamental physiological parameter rather than a single molecular target (Source: Boron & Boulpaep, Medical Physiology). Maintaining pH homeostasis is vital for protein stability, enzymatic reactions, and membrane potential, with intracellular pH typically held near 7.2 and extracellular pH near 7.4 (Source: PubMed, PMID: 23527011). In many diseases, particularly cancer, this balance is disrupted; tumors often exhibit an "acidic" extracellular environment that facilitates invasion and immune evasion while maintaining an alkaline intracellular environment to support proliferation (Source: Nature Reviews Cancer, 2019). Although pH itself is not a protein, it is the functional endpoint for numerous therapeutic interventions targeting proton pumps, carbonic anhydrases, and ion exchangers (Source: Journal of Clinical Investigation, 2013). Modulating the proton pool is a strategy used to treat conditions ranging from gastric acid disorders to systemic metabolic imbalances and is an emerging area in oncology for improving drug delivery and efficacy (Source: PubMed, PMID: 28651611).

Other names

Proton poolHydrogen ion concentrationAcid-base statusH+ concentration

Drugs interact with the proton pool through direct chemical neutralization, buffering, or by inhibiting the molecular machinery (pumps and transporters) responsible for proton secretion and pH maintenance (Source: StatPearls, Acid-Base Balance).