Gastric acid and pepsin

Gastric luminal protons (hydrochloric acid) and pepsin activity represent the primary aggressive factors in the stomach's digestive environment (StatPearls, NBK535425). Hydrochloric acid is secreted by parietal cells via the H+/K+ ATPase pump, creating a highly acidic environment (pH 1-3) necessary for the activation of the zymogen pepsinogen into the active protease pepsin (PubChem, CID 16218657). Pepsin is a major aspartic protease responsible for the initial digestion of dietary proteins by cleaving peptide bonds (PubMed, 17478444). While essential for nutrient breakdown and defense against ingested pathogens, an imbalance between these aggressive factors and mucosal defensive mechanisms (such as mucus and bicarbonate) leads to acid-peptic diseases. These conditions include peptic ulcer disease, gastroesophageal reflux disease (GERD), and laryngopharyngeal reflux (LPR), where pepsin can cause extra-gastric tissue damage even at non-acidic pH levels (StatPearls, NBK534792). Therapeutic strategies targeting these luminal factors include direct neutralization of protons using antacids and the use of cytoprotective agents like sucralfate or alginates that sequester pepsin and provide a physical barrier against acid-induced injury (StatPearls, NBK551527).

Other names

Gastric luminal protonsPepsin activityAcid-pepsin complexGastric juice acidityGastric luminal environment

Direct chemical neutralization of luminal protons and sequestration or inhibition of pepsin proteolytic activity.