Flashcards in 2.13 Purines and Pyrimidines Deck (25)
Difference between ribonucleotides and deoxyribonucleotides
2' position has an OH group on Ribonucleotides
2' position has an H group on Deoxyribonucleotides
what kind of a linkage exists between nucleotides
3' to 5'
What are the precursor molecules to Purine Synthesis
Precursors for Pyrimidine Synthesis
What is the general precursor for synthesis of NT
Ribose 5 phosphate
T or F, Pyrimidines have two rings, 1- 5 membered ring and 1- 6 membered ring
False, This is true for PUrines
Where does purine synthesis occur?
Liver and partly in peripheral tissues
What reaction occurs to form the activated PRPP
Ribose 5 Phosphate + ATP = PRPP
What enzyme catalyzes the reaction to activate PRPP
How is PRPP used differently in Purine and Pyrimidine synthesis?
Purine: Sugar is assembled from PRPP and added to a base
Pyrimidine: Base is assembled and then added to PRPP (sugar)
What are the "parent" molecule in both purine and pyrimidine biosynthesis
What is the rate limiting step in Purine Synthesis
PRPP--> 5 phosphoribosyl 1-amine
What enzyme catalyzed the rate-limiting step in Purine synthesis
What is the rate limiting step in Pyrimidine synthesis
Precursors --> Carbamoyl Phosphate
What enzyme catalyzes the rate-limiting step in Pyrimidine synthesis
Carbamoyl Phosphate Synthetase II
What inhibits CPS II in pyrimidine synthesis ?
Where does the rate limiting step of Pyrimidine synthesis occur?
Cytosol (Note: CPS 1 occurs in mitochondria)
What enzyme catalyzes conversion of Ribonucleotides to Deoxyribonucleotides?
What must be oxidized for the conversion of Ribonucleotides to Deoxyribonucleotides?
What are the two enzymes involved in Purine base salvage
Adenine Phosphoribosyl Transferase
Hypoxanthine-Guanine Phosphoribosyl transferase
What may occur because of a deficiency to HGPRT?
20% of gout occurs due to this enzyme deficiency
In case of AMP, what amino acid provides the NH group?
In the case of GMP, what amino acid provides the NH group
What causes Gout?