Fig. 4

TCA cycle labeling from U-¹³C lactate is decreased when whole cells are treated with oxamate, but not when whole cells are treated with GSK-2837808A. These results are consistent with oxamate (oxa) inhibiting cytosolic and mitochondrial LDH, but with GSK-2837808A (GSK) only inhibiting cytosolic LDH. HeLa cells were labeled with U-¹³C lactate for 24 h prior to analysis of whole-cell extracts by LC/MS. Data shown are averages from groups of n = 3. ***p < 0.001. n.s., no statistical significance. Left y axis shows labeling from 0 to 100%. Right y axis shows a zoomed-in scale for ¹³C isotopologues (inset)