FCCP, or Carbonyl cyanide p-trifluoromethoxyphenylhydrazone, is an uncoupling agent used primarily in biochemical research. It functions by disrupting the proton gradient across mitochondrial membranes, which ultimately inhibits ATP synthesis while promoting electron transport chain activity. This unique property allows FCCP to play a significant role in studies involving cellular respiration, mitochondrial function, and metabolic regulation.