Complex sentence: At the level of the citric acid cycle, arsenic inhibits lipoic acid, which is a cofactor for pyruvate dehydrogenase; and by competing with phosphate it uncouples oxidative phosphorylation, thus inhibiting energy-linked reduction of NAD +, mitochondrial respiration and ATP synthesis.
Split into simpler sentences: At the level of the citric acid cycle, arsenic inhibits lipoic acid, which is a cofactor for pyruvate dehydrogenase. In addition, by competing with phosphate arsenate uncouples oxidative phosphorylation, thus inhibiting energy-linked reduction of NAD +, mitochondrial respiration and ATP synthesis.