Figure: purine nucleobase metabolic process (GO:0006144)¶
This figure illustrates the purine nucleobase metabolic process in Schizosaccharomyces pombe (fission yeast), depicting both de novo synthesis and salvage pathways.
The de novo pathway (green arrows) begins with phosphoribosyl pyrophosphate (PRPP) and proceeds through multiple enzymatic steps catalyzed by the ade gene products (blue boxes) to produce inosine monophosphate (IMP), the central intermediate in purine metabolism.
The salvage pathways (purple arrows) utilize purine bases (adenine, guanine, hypoxanthine, and xanthine) imported from the extracellular environment via transporters (SPBC887.17) or generated intracellularly. These bases are converted to nucleotides through enzymes like apt1 (adenine phosphoribosyltransferase) and hpt1 (hypoxanthine-guanine phosphoribosyltransferase).
From IMP, the pathway branches to form either adenine nucleotides (AMP, ADP) or guanine nucleotides (GMP, GDP, GTP). Key enzymes in these conversions include ade2 (adenylosuccinate synthase), ade8 (adenylosuccinate lyase), gua1 (IMP dehydrogenase), and gua2 (GMP synthase).
The nucleotide kinases adk1 (adenylate kinase), guk1 (guanylate kinase), and ndk1 (nucleoside diphosphate kinase) catalyze phosphorylation steps to generate the di- and triphosphate forms of the nucleotides essential for cellular function.
Feedback from AI on figure:
{"feedback":"The diagram effectively shows the purine nucleobase metabolic process with clear labeling of enzymes, transporters, and molecules involved in both de novo synthesis and salvage pathways. The pathways are color-coded for readability, and the inclusion of a legend aids in understanding the different components and pathways. The spacing between elements provides good clarity, and the flow of the metabolic process is easy to follow.","necessary_changes":null,"optional_changes":null}