Figure 2From: Comparative genomics of nucleotide metabolism: a tour to the past of the three cellular domains of lifeSalvage routes of nucleotide and de novo biosynthesis starting from IMP. In red are the enzymatic steps associated with the LCA; in pink, enzymatic steps with dubious taxonomical distribution pattern to be associated to the LCA are shown; in blue, enzymatic steps not associated to the LCA. The enzymatic step associated with the guanylate kinase family is indicated with a star.Back to article page