NUCLEOTIDES Flashcards
Structural analog of folate, selectively inhibits bacterial dihydrofolate reductase
Trimethoprim
Affected enzyme in Severe Combined Immunodeficiency Syndrome (SCID)
Adenosine Deaminase
Donors of atoms for PYRIMIDINE SYNTHESIS
- Glutamine (Q)
- Aspartate (D)
- CO2
- Enzyme Deficiency: HGPRT
- Clinical Presentation:
- ↑ PRPP and uric acid leads to gout
- Self-mutilation, mental retardation o X-linked disease
LESCH-NYHAN SYNDROME
Synthesis of Purine
o Accumulation of deoxyadenosine derivatives (↑ dATP) inhibits ribonucleotide reductase, leading to lack of DNA synthesis in immune cell precursors
o May present as severe combined immunodeficiency
o Absent thymus, no T-cell or B-cell production
(lymphocytopenia)
o Death before age 2 because of overwhelming infection
o Treat with bone marrow transplant, gene therapy
ADENOSINE DEAMINASE DEFICIENCY
How many rings does a pyrimidine have?
1
NucleoSides
BS: Base + Sugar only
rate limiting enzyme for PYRIMIDINE SYNTHESIS
Carbamoyl phosphate synthetase II
Donors of atoms of PURINE SYNTHESIS
- glutamine (Q)
- Aspartate (D)
- CO2
- Glycine (G)
- N10-formyltetrahydrofolate (Vit B9)
Nucleotides composition
BSP: Base + Sugar + Phosphate.
Reversible inhibitor of IMP dehydrogenase, depriving T and B lymphocytes of nucleic acids
Mycophenolate
Purine Salvage Pathway
- Converts dUMP to thymine
- Cofactor: N 5 ,N 10 -methylene tetrahydrofolate
- Inhibited by 5-fluorouracil
Thymidylate synthase