HEPES, Free Acid

HEPES powder is a zwitterionic biological buffer ideally suited for cell culture due to its ability to maintain physiological pH despite changes in carbon dioxide concentration. This property distinguishes HEPES from bicarbonate buffers which are also used in cell culture applications. Another characteristic of HEPES is that its disassociation decreases as temperature decreases making it a more effective buffer agent for maintaining enzyme structure and function at low temperatures.