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Prebiotic syntheses of vitamin coenzymes: II. Pantoic acid, pantothenic acid, and the composition of coenzyme APantoic acid can by synthesized in good prebiotic yield from isobutyraldehyde or alpha-ketoisovaleric acid + H2CO + HCN. Isobutyraldehyde is the Strecker precursor to valine and alpha-ketoisovaleric acid is the valine transamination product. Mg2+ and Ca2+ as well as several transition metals are catalysts for the alpha-ketoisovaleric acid reaction. Pantothenic acid is produced from pantoyl lactone (easily formed from pantoic acid) and the relatively high concentrations of beta-alanine that would be formed on drying prebiotic amino acid mixtures. There is no selectivity for this reaction over glycine, alanine, or gamma-amino butyric acid. The components of coenzyme A are discussed in terms of ease of prebiotic formation and stability and are shown to be plausible choices, but many other compounds are possible. The gamma-OH of pantoic acid needs to be capped to prevent decomposition of pantothenic acid. These results suggest that coenzyme A function was important in the earliest metabolic pathways and that the coenzyme A precursor contained most of the components of the present coenzyme.
Document ID
20040112278
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Miller, S. L.
(University of California San Diego, La Jolla 92093-0317)
Schlesinger, G.
Date Acquired
August 21, 2013
Publication Date
April 1, 1993
Publication Information
Publication: Journal of molecular evolution
Volume: 36
Issue: 4
ISSN: 0022-2844
Subject Category
Exobiology
Funding Number(s)
CONTRACT_GRANT: NAGW2-0
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Number 52-20
NASA Program NSCORT
NASA Discipline Number 93-10
NASA Program Exobiology
Non-NASA Center
NASA Discipline Exobiology

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