HEPES Sodium salt (CAS 75277-39-3)

HEPES Sodium Salt, chemically known as N-(2-hydroxyethyl)piperazine-N′-(2-ethanesulfonic acid) sodium salt, is a zwitterionic biological buffer used extensively in biochemical and cellular biology research to maintain the pH of solutions. Its buffering range, typically between pH 7.2 and 7.4, closely aligns with the physiological pH of most living organisms, making it invaluable for experiments involving live cells. HEPES is particularly favored for its minimal interference with biochemical reactions and very low UV absorbance, which is crucial for UV-sensitive experiments. The mechanism of action of HEPES in buffering involves the sulfonic acid group which can donate a hydrogen ion (proton) when the pH starts to rise (becomes too basic) and the piperazine ring which can accept a hydrogen ion when the pH starts to drop (becomes too acidic). This ability to stabilize the pH makes it a preferred choice in cell culture systems, where maintaining an optimal, stable pH is critical for cell health and accurate experimental outcomes. Additionally, HEPES is used in various molecular biology protocols including DNA/RNA extractions and enzyme reactions, where maintaining precise pH is necessary for the activity and stability of enzymes and other macromolecules. Its effectiveness in preventing pH drift in rapidly proliferating cultures also makes it a common component in media for growing mammalian cells for research that requires highly controlled environmental conditions.