Hypothetical model of the interaction between GLDH and the mitochondrial electron transport chain. GLDH feeds electrons into Cyt c between complexes III and IV, while GL is converted into ascorbate. The inhibition of Cyt c oxidase by KCN in complex IV blocks ascorbate production, possibly by the accumulation of electrons in Cyt c. AOX, Alternative oxidase; DH, dehydrogenase; UQ, ubiquinone.