Succinate ubiquinone oxydoreductase

NO has a cytostatic effect by inhibiting ATP synthesis [99] via Kreb s cycle (aconitase inhibition, [100]), glycolysis (GADPH inhibition) and mitochondrial respiration (NAD ubiquinone oxydoreductase and succinate ubiquinone oxydoreductase inhibitions, [101]). Another pathway is the ornithine decarboxylase inhibition. This enzyme is implicated in polyamine production necessary to cell proliferation and its activity is inhibited by NO in human colon cancer cells HT-29 and Caco-2 [102]. Furthermore NO directly inactivates ribonucleotide reductase [103] of TA3 cancer cells (murine breast cancer cells) [104]. This enzyme controlling DNA synthesis catalyses desoxyribonucleotides synthesis, and its inhibition blocks cells in S phase. This inhibition is rapid and reversible in K562 and TA3 cells [105]. 

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