Table 4.

Parallels between ROI and RNI

Feature	ROI	RNI
Primary catalyst	Multisubunit flavocytochrome	Multisubunit flavocytochrome
Substrates	O2, NADPH	O2, NADPH, l-arginine
Primary product	Inorganic radical (O2⨪)	Inorganic radical (⋅NO)
Actions at low levels	Activate or inhibit receptors, enzymes, transcription factors	Activate or inhibit receptors, enzymes, transcription factors
Actions at high levels	Cause mutagenesis, apoptosis, necrosis	Cause mutagenesis, apoptosis, necrosis
Basis of cellular resistance	SODs; catalase; peroxiredoxins; redox cycles involving glutathione, thioredoxin, glutaredoxin, trypanothione, ovothione, mycothione; methionine sulfoxide reductase; ascorbate; γ-tocopherol; urate; α-keto acids	Under study