Crystal Arthropathies Flashcards
(48 cards)
which base is N-containing single ring structure
pyrimindine
which base is N-containing double ring structure
purine
which nucleotides are purines
A and G
which nucleotides are pyrimidines
C, T, and U
difference in DNA and RNA for nucleotides
DNA has T and RNA has U
what are the two pathways to synthesize purines?
de novo synthesis pathway and salvage pathway
explain the de novo pathway to synthesize purines
Glutamine is used to transfer an N to PRPP, then a base is built on the N, the nucleotide product is inosine monophosphate (IMP)
what is used in the de novo synthesis pathway?
glutamine
what is the nucleotide product of the de novo synthesis pathway
inosine monophosphate (IMP)
IMP can then be used to make what?
AMP or GMP
ATP to make GMP
GTP to make AMP
why is reciprocal control in the de novo synthesis useful?
Helps ensure you are not making all of one type of purine and not enough of the other
what purine base is made from the de novo synthesis pathway?
hypoxanthine
what does the salvage pathway use?
Uses hypoxanthine, guanine, and adenine bases that already exist
what are the two enzymes used in the salvage pathway?
- hypoxanthine-guanine phosphoribosyl transferase
- adenine phosphoribosyltransferase
what does hypoxanthine-guanine phosphoribosyl transferase do?
catalyzes the addition of phosphoribose (sugar +P) from PRPP to:
- Hypoxanthine to make IMP
- guanine to make GMP
what does adenine phosphoribosyltransferase do?
catalyzes the addition of phosphoribose (sugar + P) from PRPP to:
adenine to make AMP
what is the pathway for pyrimidine nucleotide synthesis
de novo pathway
how is the de novo pathway different in pyrimidine than purine synthesis
in purimidine, it involves making an intermediate pyrimidine ring first, then attaching a ribose-5-P (via PRPP)
what are the substrates for the pyrimidine ring in pyrimidine synthesis
- carbamoyl phosphate (made from glutamine, ATP, CO2)
- aspartate
during the de novo pathway for pyrimidine, what is the nucleotide intermediate when the pyrimidine ring is attached to PRPP?
UMP
how is CTP made from UMP
UMP is phosphorylated via kinases to make UTP, UTP is aminated to make CTP (glutamine provides the N)
how to make dTMP from UMP
UMP is phosphorylated (kinase) to make UDP, then converted to dUMP, dUMP is methylated to dTMP using folate coenzyme
what removes P’s from nucleotides to relase nucleosides
nucleotidases
what happens when pyrimidine bases are degraded
cytosine to uracil and ultimately alanine
