Nitric Oxide Dioxygenase - Physiological Function

Physiological Function

Historically, nitric oxide dioxygenase (around 1.8 billion years ago) served to provide the modern day analogue of hemoglobin/myoglobin function for oxygen storage and transport. Gardner et al. (1998) suggested that the first hemoglobin/myoglobin probably functioned as an enzyme utilizing bound ‘activated’ oxygen gas to dioxygenate NO in microbes.

The wide diversity of multicellular organisms benefitting from the oxygen storage and transport functions of myoglobin/hemoglobin appeared much later (approximately 0.5 billion years ago).

NODs are now known to serve two important physiological functions in diverse life forms: they prevent NO toxicity (otherwise known as "nitrosative stress") and regulate NO signalling. NODs belong to the larger family of well-established free radical and reactive oxygen detoxifying enzymes that includes superoxide dismutase, catalase, and peroxidase.