Final: Lecture 34 Flashcards
BIG NAME SMALL RING
- Purine, small name big ring
* Pyrimidine, big name, small ring
Nucleic acids are _______, Nucleotides contain ________, Nucleosides contain _______.
- Polynucleotides
- Base-Sugar-Phosphate
- Base-Sugar
Phosphoribosyl pyrophosphate (PRPP)
- Central constituent of nucleotide metabolism
- Synthesized from ribose phosphate and ATP
- Purine start with a sugar, then attach other things
The committed step in the purine synthesis is the formation of the _______.
- Phosphoribosyl amine
* Forms hypoxanthine ribose phosphate or inosine monophosphate
Atoms are then sequentially added to the phosphoribosly amine
•Building each ring structure from amino acids and carbons
They synthesis of purine nucleotides is controlled by _______ at several sites to balance the production pf purine nucleotides.
•Feedback regulation
PRPP inhibited by?
•IMP, AMP, and GMP
IMP to Adenylo-succinate inhibited by?
•AMP
IMP to xanthylate inhibited by?
•GMP
AMP synthesis is stimulated by ____. GMP synthesis is stimulated by ___.
- GTP
* ATP
The pyrimidine ring is synthesized from carbamoyl phosphate and aspartate by _________.
- Aspartate-transcarbamoylase
* Committed step is formation of n-carbamoyl aspartate from aspartate and carbamoyl phosphate
The main intermediate that forms uricle is?
•Orotic acid
The two major control points of pyrimidine biosynthesis are:
- Carbamoyl phosphate synthetase is inhibited by UMP and purines and stimulated by PRPP
- Aspartate transcarbamoylase is feedback inhibited by CTP.
The immediate H+ donor for the reduction of ribonucleoside disphosphate is reduced _________ or ________.
- Thioredoxin
* Glutaredoxin
Humans excrete _________ in the urine in the form of sodium urate.
•Uric acid
