From the hydride electron pair, one electron is transferred to the positively charged nitrogen of the nicotinamide ring of NAD, and the second hydrogen atom transferred to the C4 carbon atom opposite this nitrogen. The midpoint potential of the NAD/NADH redox pair is −0.32 volts, which makes NADH a strong "reducing" agent. The reaction is easily reversible, when NADH reduces another molecule and is re-oxidized to NAD. This means the coenzyme can continuously cycle between the NAD and NADH forms without being consumed.