What is proton pumping?

As a subject matter expert in biochemistry, I can explain the process of proton pumping. Proton pumping is a mechanism used by cells to create a proton gradient across a biological membrane. This is achieved through the action of a specific type of integral membrane protein known as a proton pump. These pumps work by transferring protons (H+ ions) from one side of the membrane to the other, effectively creating a concentration difference. This gradient is not just a simple accumulation of protons; it is a difference in pH across the membrane, which cells can harness as a form of potential energy. The proton gradient has several important functions in the cell. For instance, it is critical for creating the electrochemical gradient necessary for ATP synthesis in mitochondria and chloroplasts. Additionally, the proton gradient can be used to drive the transport of other molecules against their concentration gradient, a process known as secondary active transport. In the context of the cell's plasma membrane, the sodium-potassium pump is an example of a proton pump. It moves three sodium ions out of the cell and two potassium ions into the cell, contributing to the resting membrane potential, which is essential for nerve cell function.

A proton pump is an integral membrane protein that builds up a proton gradient across a biological membrane.