Fig 1.

Redox biology of metazoans. Metazoans depend upon redox processes to support energetics, metabolic and structural organization, separation from and defense against external environment, and reproduction. The overall redox structure is a complex network including small molecules, measured by redox metabolomics, and proteins, measured by redox proteomics. Metal ions derived from the environment are a major variable not explicitly shown, but impact both the redox metabolome and redox proteome by interfering with essential metal ion functions and catalyzing non-enzymatic reactions. The enzymology of redox reactions has been studied in detail and organized by the Enzyme Commission in terms of electron donors and electron acceptors in enzyme-catalyzed reactions (see http://www.chem.qmul.ac.uk/iubmb/enzyme/EC1/). No systematic consideration of the redox metabolome is currently available. The elements of the redox proteome are mostly known, but systematic knowledge of spatial and temporal distributions is not available. Redox systems biology provides an initial framework for development, but quantitative data for abundance and kinetics are limited. Ultimately, this knowledge is needed to understand and develop strategies to improve healthy longevity.