Hydrogen Sulfide Oxidation: Adaptive Changes in Mitochondria of SW480 Colorectal Cancer Cells upon Exposure to Hypoxia

Figure 4

Adaptive changes occurring in mitochondria in response to hypoxia. Upon prolonged exposure to hypoxia, mitochondria become less abundant, but enriched in sulfide:quinone oxidoreductase (SQR). Consistently, their maximal sulfide-oxidizing activity increases, while overall decreasing in the cell. These changes are proposed to occur to prevent H₂S inhibition of cytochrome c oxidase (CcOX) and thus protect cell respiration from H₂S poisoning.