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Early steps of metabolism evolution inferred by cladistic analysis of amino acid catabolic pathways


By Cyril - Posted on 17 April 2014

TitleEarly steps of metabolism evolution inferred by cladistic analysis of amino acid catabolic pathways
Publication TypeMiscellaneous
Year of Publication2002
AuthorsCunchillos C, Lecointre G
AbstractAmong abiotic molecules available in primitive environments, free amino acids are good candidates as the first source of energy and molecules for early protocells. Amino acid catabolic pathways are likely to be one of the very first metabolic pathways of life. Among them, which ones were the first to emerge? A cladistic analysis of catabolic pathways of the sixteen aliphatic amino acids and two portions of the Krebs cycle is performed using four criteria of homology. The cladogram shows that the earliest pathways to emerge are not portions of the Krebs cycle but catabolisms of aspartate, asparagine, glutamate, glutamine, proline, arginine. Earliest enzymatic catabolic functions were deaminations and transaminations. Later on appeared enzymatic decarboxylations. The consensus tree allows to propose four time spans for catabolism development and corroborates the views of Cordon in 1990 about the evolution of catabolism. (C) 2002 Academie des sciences / Editions scientifiques et medicales Elsevier SAS.