Figure 4.

Patient fibroblasts show reduced complex IV/ citrate synthase activities but no significant differences in oxygen consumption rate. (A) Spectrophotometrically determined complex IV (CIV) activity is significantly decreased in Patient 2, when normalized to protein amount. Patient 2 complex IV activity was similar to the control. (B) Citrate synthase (CS) activity of Ptient 1 is significantly increased whereas there is no difference between the control and Patient 2. (C) Complex IV activity normalized to citrate synthase activity show that both Patients 1 and 2 have a significantly lower activity when compared to the control. Statistical analysis was performed with one-way ANOVA followed by the Bonferroni multiple comparison test. *P < 0.05, **P < 0.01, control versus patient. (D) Representative graph displaying the oxygen consumption rate (OCR) of control and patient cells (blue line, control; orange line, Patient 1 and green line, Patient 2). Oligomycin (Oligo), FCCP and rotenone plus antimycin A (R + A) were sequentially injected in each well. The error bars indicate the mean ± standard deviation of triplicates of one experiment. The bioenergetic parameters were not significantly different between the control and patients. Data analysis is presented as mean ± standard error of the mean of three separate experiments (duplicates or triplicates of each sample were analysed each time).