The Stability of Low-Valent Iron Porphyrins in Electrochemical Solutions

Abstract

The geosphere and atmosphere upon which plants and auxotrophic bacteria depend for growth and reproduction contain three key elements: carbon, nitrogen, and sulfur which are present in a relatively oxidized state. These species must be reduced for incorporation into biological material. Carbon dioxide must be reduced to the carbohydrate or fatty acid oxidation state, sulfate to the sulfide stage for incorporation into the sulfur-containing amino acids, and nitrogen must be reduced from elemental dinitrogen or nitrate to the ammonia oxidation state for incorporation into nitrogencontaining amino acids\u27. As such, electron transfer plays an important role in the function of natural systems. A large number of highly specific and diverse enzymatic systems have evolved to catalyze these electron transfer reactions in vivo. Among the many electron transfer reactions that are known, one of particular interest is the enzymatic reduction of inorganic nitrate which plays a major role in nitrogen cycle in the biosphere2 (Figure 1-1)..