In comparing the de novo synthesis of IMP and UMP, which one of the following best represents commonalities in the pathways?
High-Yield Explanation
De novo purine and pyrimidine biosynthesis occurs in the liver and, to a limited extent, in the brain.In pyrimidine biosynthesis, carbamoyl phosphate, produced from glutamine, CO2 , and ATP, reacts with aspartate to form a base that, after oxidation, reacts with phosphoribosyl pyrophosphate (PRPP) to form a nucleotide. This nucleotide is decarboxylated to form UMP. In purine biosynthesis, the base is produced on ribose-5-phosphate, which is generated from PRPP. Glycine is incorporated into the precursor, and tetrahydrofolate derivatives donate carbons 2 and 8 as IMP is formed. Glutamine is a nitrogen donor for both purine and pyrimidine biosynthesis. Aspartate is required for both UMP and IMP synthesis. Aspartate is also required in the conversion of IMP to AMP.