Free Radical Chemistry as Related to Degradative Mechanisms

Fungal systems have harnessed the power of reactive oxygen species to achieve breakdown of one of the world's toughest substances, wood. To attain this goal, powerful oxidizing agents must be used. However, such agents present a risk to the fungal cells generating them. If they are highly reactive, there is a further risk that they will be dissipated in non-productive reactions with environmental biomolecules unless they are selectively delivered to their sites of action. Let us examine the basic chemistry of some reactive species to see what might be possible. Oxidations by oxygen Oxygen itself is a biradical, containing two unpaired electrons. The parallel spin of these two electrons makes it difficult for oxygen to react directly with nonradicals. As a result, direct oxidation of most biomolecules with O2 is slow. Wood is the perfect example; it resists direct oxidation by O2 for centuries. However oxygen does react fast with