Fig. 5.

Loss of ECHS1 expression reduces mitochondrial respiratory and enzymatic function. (A) ECHS1 KO mitochondria have reduced levels of CI and CIV activity (normalised to citrate synthase, CS, activity), whereas CII and CII + CIII activity is unchanged compared to control (CON). (B) ECHS1 KO mitochondria have reduced complex I, complex IV and citrate synthase activities (raw rates) compared to control (CON) rates. (C) Basal and maximal respiration rates in ECHS1 KO cells were both significantly reduced when metabolising glucose. (D) Basal and maximal respiration rates in ECHS1 KO cells were both significantly reduced when metabolising the fatty acid ester palmitoyl‐l‐carnitine. (E) ECHS1 KO mitochondria have reduced state IV respiratory rates when metabolising glutamate and malate or pyruvate and malate, but not succinate. (F) Average change in H₂DCFDA fluorescence intensity in CON and ECHS1 KO cells under basal and inhibitory conditions. Cellular H₂O₂ production was decreased after treatment with rotenone (Rot) or antimycin A (AntA) in CON cells. However, only antimycin A treatment reduced H₂O₂ production in ECHS1 KO cells. Data shown as mean ± SD, n = 3. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 relative to control (CON), ^# P < 0.05 compared to ECHS1 KO (Student's two‐tailed t‐test).