Micellar catalysis plays a crucial role in NO metabolism because media in vivo are heterogeneous and the concentration of NO in different phases at different levels of solubility differs by degrees of magnitude. The relative volumes of the hydrophobic phases are usually small. At small volumes (which are calculated) of these phases the reaction rates of NO metabolism change. The dependence on the relative volumes is resonance-like. Not only regulation, but bifurcations and catastrophes are possible in vivo as a result of this changing due to the small change of effectiveness of micellar catalysis.