Figure 1

Cellular pathways interacting with RNA metabolism. A: purine de novo biosynthesis and histidine metabolism. Involved key enzymes: 1) 5'-nucleotidase (EC 3.1.3.5), 2) AICAR transformylase (EC 2.1.2.3), 3) adenylsuccinate synthetase (EC 6.3.4.4), 4) adenylsuccinate lyase (EC 4.3.2.2, catalyzes both conversion of succinyl-AMP into AMP and SAICAR (N-succinyl-5-amino-imidazol-4-carboxamid-ribonucleotid into AICA ribotide), 5) histidine decarboxylase (EC 4.1.1.22), 6) phosphatases and 5'-nucleotidase, bold: analyzed metabolites; abbreviations: PRPP (5-phospho-ribosyl-1-pyrophosphate); for all other abbreviations, refer to text. B: polyamine/methionine cycle. Involved key enzymes: 1) S-adenosylmethionine decarboxylase (EC 4.1.1.50), 2) ornithine decarboxylase (EC 4.1.1.17), 3) propylaminotransferase 1 (EC 2.5.1.16), 4) propylaminotransferase 2 (EC 2.5.1.22), 5) oxygenases, 6) methylthioadenosine phosphorylase (EC 2.4.2.28), 7) DNA-(5-cytosine)-methyltransferase (EC 2.1.1.37), 8) tRNA-uridine aminocarboxypropyltransferase (EC 2.5.1.25),); bold: analyzed metabolites; abbreviations: put (putrescine), spd (spermidine), spm (spermine), dcSAM (decarboxylated SAM), MTR-1P (S-methyl-5'-thio-D-ribose-1-phosphate); for all other abbreviations, refer to text.