Chapter 23: Nucleotide Metabolism Flashcards
Nucleotides are ?
Building blocks of nucleic acid, DNA/RNA
Nucleotide:
Phosphate esters of a pentose in which a purine/pyrimadine is linked to C1 of sugar.
Purines:
Adenine and guanine
Pyrimadines:
Cytosine, thymine, and uracil.
What did John Buchanan do?
Determined the origins of the atoms that compromise purines - by looking at uric acid production.
How does the synthesis of purine ribonucleotides work?
Initially starts with inosine monophosphate (IMP) with hypoxanthine as its base.
IMP is the precursor for ?
AMP and GMP
Purines are initially formed as ___________ rather than as free bases.
ribonucleotides
Purine synthesis yields?
Inosine monophospahte (IMP)
Diagram of ribose-5-phosphate (R5P) into IMP:
Where is purine biosynthesis regulated?
IMP, ATP, and GTP pathways
1st purine salvage pathways:
Adenine > AMP
Catalyzed by adenine phosphoribosyl transferase. PRPP in, PPi out
2nd purine salvage pathways:
Hypoxanthine > IMP
Guanine > GMP
1st committed step of purine biosynthesis?
Phosphorylating ribose-5-phosphate to PRPP
How are pyrimidines synthesized?
N1, C4, C5, and C6 comes from aspartate/aspartic acid
N3 comes from glutamine
C2 comes from HCO3