Ferrous-ascorbate complexes as carriers of nitric oxide.

Ferrous-ascorbate is known to form with nitric oxide paramagnetic nitrosyl ferrous-ascorbate complexes, Fe-AA-NO. These complexes yield on EPR signal with g-factor close to 2.02 and an optical absorption spectrum with maxima at 340, 460, and 600 nm. Fe-AA-NO complexes are unstable in the presence of oxygen. Ferrous-ascorbate complexes promote NaNO2 decay resulting in the formation of NO. Nitric oxide is taken up by Fe-AA complexes to form paramagnetic ferrous-ascorbate nitrosyl complexes, Fe-AA-NO. It is suggested that ferrous-ascorbate complexes can play the role of carriers of NO and, perhaps, O2 in the blood plasma. Nitrosyl ferrous-ascorbate complexes can also be the NO containing factor involved in the blood vessel relaxation (endothelium-derived relaxing factor, EDRF).