The ability to detect oxygen availability is a ubiquitous attribute of aerobic organisms.
However, the mechanism(s) that transduce oxygen concentration or availability into appropriate
physiological r Show more
The ability to detect oxygen availability is a ubiquitous attribute of aerobic organisms.
However, the mechanism(s) that transduce oxygen concentration or availability into appropriate
physiological responses is less clear and often controversial. This review will make the case for
oxygen-dependent metabolism of hydrogen sulfide (H2 S) and polysulfides, collectively referred to as
reactive sulfur species (RSS) as a physiologically relevant O2 sensing mechanism. This hypothesis
is based on observations that H2 S and RSS metabolism is inversely correlated with O2 tension,
exogenous H2 S elicits physiological responses identical to those produced by hypoxia, factors that
affect H2 S production or catabolism also affect tissue responses to hypoxia, and that RSS efficiently
regulate downstream effectors of the hypoxic response in a manner consistent with a decrease in O2 .
H2 S-mediated O2 sensing is then compared to the more generally accepted reactive oxygen species
(ROS) mediated O2 sensing mechanism and a number of reasons are offered to resolve some of the
confusion between the two.
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