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. Author manuscript; available in PMC: 2016 Jul 30.
Published in final edited form as: Cell. 2015 Jul 30;162(3):552–563. doi: 10.1016/j.cell.2015.07.017

Figure 1. Cytochrome B Mutant 143B Cybrid Cells are Auxotrophic for Electron Acceptors that can Regenerate NAD+.

Figure 1

(A) Proliferation rate of 143B CytB cells was determined in the presence or absence of pyruvate. (left) Cell counts, normalized to cell number at t=0 when media conditions were applied, were assessed over time and used to calculate proliferation rate (right). (B) Pyruvate is a substrate of lactate dehydrogenase (LDH), accepting electrons from NADH to produce NAD+ and lactate. (C) Alpha-ketobutyrate (AKB) can also act as an electron acceptor from NADH and yield NAD+ and alpha-hydroxybutyrate (AHB). (D) Proliferation rate for 143B CytB cells in the presence or absence of AKB was determined as in (A). (E) Intracellular ratio of NAD+/NADH was determined in 143B CytB cells in untreated media or in the presence of pyruvate (Pyr) or AKB. (F) The concentration of AKB and AHB in the media of 143B CytB cells cultured in the presence of AKB was determined over time by GCMS analysis. Values in all figure panels denote mean ± standard error of the mean (SEM), n=3. See also Figure S1.