RT Journal
A1 Peregrin-Alvarez, José Manuel
A1 Tsoka, Sophia
A1 Ouzounis, Christos A.
T1 The Phylogenetic Extent of Metabolic Enzymes and Pathways
JF Genome Research 
JO Genome Research 
YR 2003 
FD March 01 
VO 13 
IS 3 
SP 422 
OP 427 
DO 10.1101/gr.246903 
UL http://genome.cshlp.org/content/13/3/422.abstract 
AB The evolution of metabolic enzymes and pathways has been a subject of intense study for more than half a century. Yet, so far, previous studies have focused on a small number of enzyme families or biochemical pathways. Here, we examine the phylogenetic distribution of the full-known metabolic complement of Escherichia coli, using sequence comparison against taxa-specific databases. Half of the metabolic enzymes have homologs in all domains of life, representing families involved in some of the most fundamental cellular processes. We thus show for the first time and in a comprehensive way that metabolism is conserved at the enzyme level. In addition, our analysis suggests that despite the sequence conservation and the extensive phylogenetic distribution of metabolic enzymes, their groupings into biochemical pathways are much more variable than previously thought.