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Sugars as the optimal biosynthetic carbon substrate of aqueous life throughout the universeOur previous analysis of the energetics of metabolism showed that both the biosynthesis of amino acids and lipids from sugars, and the fermentation of organic substrates, were energetically driven by electron transfer reactions resulting in carbon redox disproportionation (Weber, 1997). Redox disproportionation--the spontaneous (energetically favorable) direction of carbon group transformation in biosynthesis--is brought about and driven by the energetically downhill transfer of electron pairs from more oxidized carbon groups (with lower half-cell reduction potentials) to more reduced carbon groups (with higher half-cell reduction potentials). In this report, we compare the redox and kinetic properties of carbon groups in order to evaluate the relative biosynthetic capability of organic substrates, and to identify the optimal biosubstrate. This analysis revealed that sugars (monocarbonyl alditols) are the optimal biosynthetic substrate because they contain the maximum number of biosynthetically useful high energy electrons/carbon atom while still containing a single carbonyl group needed to kinetically facilitate their conversion to useful biosynthetic intermediates. This conclusion applies to aqueous life throughout the Universe because it is based on invariant aqueous carbon chemistry--primarily, the universal reduction potentials of carbon groups.
Document ID
20040141546
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Weber, A. L.
(NASA Ames Research Center Moffett Field CA United States)
Date Acquired
August 22, 2013
Publication Date
February 1, 2000
Publication Information
Publication: Origins of life and evolution of the biosphere : the journal of the International Society for the Study of the Origin of Life
Volume: 30
Issue: 1
ISSN: 0169-6149
Subject Category
Exobiology
Distribution Limits
Public
Copyright
Other
Keywords
NASA Center ARC
NASA Discipline Exobiology

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