Hydrogen sulfide (H 2 S) is the third gasotransmitter discovered. Sulfide shares with the two
others (NO and CO) the same inhibiting properties towards mitochondrial respiration.
However, in contrast with NO or CO, sulfide at concentrations lower than the toxic (μM) level
is an hydrogen donor and a substrate for mitochondrial respiration. This is due to the activity
of a sulfide quinone reductase found in a large majority of mitochondria. An ongoing study of
the metabolic state of liver in obese patients allowed us to evaluate the sulfide oxidation …