NAD

Nicotinamide adenine dinucleotide (NAD⁺) are vital carriers of electrons in processes such as the Cyclic Acid Cycle or Photosynthesis .  The co-enzyme has the ability to "pick up" two electrons and a Hydrogen ion and is used in the cell to produce ATP.  When reduced, it becomes NADH and since it's a co-enzyme, it is able to pass on it's electrons to another carrier and is oxidised back to NAD⁺