|What are purines and pyrimidines?|
Purines and pyrimidines, often called bases, are nitrogen-containing heterocyclic compounds.
|Purine bases you will find in DNA are|
Pyrimidines have a single …….sided ring structure.
Pyrimidines have a single six sided ring structure.
| Example of Pyrimidines base |
|The pyrimidine NSs end in |
- use the NS name
- followed by “mono-“, “di-“
nMonomeric units of nucleic acids
nComponents of coenzymes
|Nucleotides are components of coenzymes: |
|Nucleotide activate intermediates like:|
Why is purine salvage pathway of metabolism of purine important?
- Because free purines are somewhat toxic.
The salvage pathway decreases the levels of PRPP, and therefore decreases the rate
of purine synthesis. This is an important regulatory mechanism for purine metabolism.
|Synthesis of purines requires|
nOne carbon units transferred via THF (2)
|GOUT is a disorder characterized by:|
|high levels of uric acid in blood, as a result of either the overproduction or under excretion of uric acid. |
nGout is treated with drug such as
|allopurinol that inhibit xanthineoxidase |
g-amide group of glutamine
|Source of carbon and nitrogen on pyrimidines are|
- 1,4,5,6 from ASparate
- 2 from HCO3-
- 3 from Glutamine amide
|Source of carbon and nitrogen atoms in purine ring|
1 from Asparate amine
2 from C1-H4folate
3 from Glutamine amide
4, 5,7 from Glycine
8 from C1 H4folate
9 from Glutamine amide
In de novo synthesis, the pyrimidine ring is synthesized from
- glutamine (or ammonium ion).
|Synthesis of pyrimidines vs. purines.|
nFirst, the ring structure is assembled as a free base in pyrimidines, not built upon PRPP like purines.
nSecond, there is no branch in the pyrimidine synthesis pathway.
In Synthesis of Pyrimidine Nucleotides, what is regulated step?
In Synthesis of Pyrimidine Nucleotides, committed step involves which enzyme?
The regulatory step in Synthesis of Pyrimidine
Nucleotides involves which enzyme?
|Regulation of Purine Synthesis|
Inactivate Purine + PRPP—-> Active Purine
Activate Purine + IMP/GMP/IMP—> Inactivate Purine
Inactivate Purine + ????—-> Active Purine
|Activate Purine +????—> Inactivate Purine|
|Metabolism of Purine Nucleotides include: |
nSynthesis of purine nucleotides
nPurine nucleotide interconversions
nGTP and tetrahydobiopterin