| Literature DB >> 11536535 |
Abstract
Pantoic 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.Entities:
Keywords: NASA Discipline Exobiology; NASA Discipline Number 52-20; NASA Discipline Number 93-10; NASA Program Exobiology; NASA Program NSCORT; Non-NASA Center
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Year: 1993 PMID： 11536535 DOI： 10.1007/bf00182178
Source DB: PubMed Journal: J Mol Evol ISSN： 0022-2844 Impact factor: 2.395