How Does Rotenone Disrupt Cellular Respiration?

Rotenone is in the class of electron transport inhibitors, which bind at some point on the transport chain, keeping electrons from moving. This stops cellular respiration from taking place at all through that particular pathway. The NADH and succinate pathways can both experience blockage this way.

Rotenone is considered a competitive electron inhibitor, which means that it permits a small amount of oxygen consumption, since a tiny flow of electrons can make it through. Even with the oxygen, though, competitive inhibitors keep the cell from retaining a suitable chemiosmotic gradient. This means that even adding ADP to the system does not boost respiration back to healthy levels.

Because of its high toxicity to humans and wildlife, rotenone is restricted from general sale and use. It still is used as an insecticide, but only by entities exempt from the restriction. Other pesticides in the electron-transport inhibitor family include antimycin, cyanide and malonate. Like rotenone, malonate is also a competitive inhibitor, although it works more to hinder the function of enzymes rather than the electron-transport process. Of the four, cyanide is the most toxic, and safety requirements mandate that storage facilities keep it in a locked area, as a small capsule can contain a fatal dose for a person.