Figure 4.

Schematic diagram of the interaction of matrix Ca²⁺ with processes involved in oxidative phosphorylation. Enzyme abbreviations: PDH: Pyruvate dehydrogenase, CS: Citrate synthase, A: Aconitase, ICD: Isocitrate dehydrogenase, KDH: α ketoglutarate dehydrogenase, SCS: Succinyl CoA synthetase, SDH: Succinate dehydrogenase (also Complex II), F: Fumarase, MDH: Malate dehydrogenase, MCU: Mitochondria calcium uniporter. The Complexes of oxidative phosphorylation are labeled as roman numerals from I-V. The DH on Complex 1 refers to the intrinsic and possibly associated NADH dehydrogenase activity. The red arrows from Ca²⁺ to the different interaction sites imply either a direct or indirection modulation of the transport or enzymatic activity.