Fig. 2.

Absolutely superessential reactions occur in most prokaryotic genomes. (A) The vertical axis shows the genome occurrence index of absolutely superessential reactions for growth on glucose and 54 carbon sources. The curves are almost congruent, underscoring that most absolutely superessential reactions are environment-general. Furthermore, a majority (73.5%) of 155 absolutely superessential reactions for growth on 54 carbon sources has a high genome occurrence (I_GO ≥ 0.5). (B) The plot shows the change in the genome occurrence index of 125 environment-general and absolutely superessential reactions when we manually improve the functional annotation of those 20 reactions that occur in fewer than 50% of genomes. Before the improvement, 105 of 125 reactions have a genome occurrence of more than 50% (○), whereas after improvement, this number increases to 118 (94.4%; ●). See Genes Responsible for Superessential Reactions Occur in Most Prokaryotic Genomes and Dataset S4 for details.