Enzymatic activities of OXPHOS complexes. Activities of complexes I, II, and IV (CI, CII, and CIV) measured spectrophotometrically in mitochondria from Pisd KD#1 and NegCtrl cells (A) and PSB-2 and WT cells (B). Data are means ± S.D. from 3 to 4 independent experiments (*, p < 0.05 versus control).