A proton pump is a type of protein found in the membranes of cells that helps transport protons (hydrogen ions) across the membrane. This process is crucial for generating energy in cells, particularly in the production of adenosine triphosphate (ATP), which is the energy currency of the cell. Proton pumps play a vital role in various biological processes, including cellular respiration and maintaining pH balance. In the context of the human body, proton pumps are especially important in the stomach, where they help produce gastric acid. This acid aids in digestion and protects against harmful bacteria. Medications known as proton pump inhibitors (PPIs) are often prescribed to reduce stomach acid production, providing relief from conditions like gastroesophageal reflux disease (GERD).