Shared Flashcard Set

Details

puridines and nucleotides
Tufts D17 Exam IV
23
Biochemistry
Professional
11/06/2013

Additional Biochemistry Flashcards

 


 

Cards

Term
Pyrimidine Skelton (ring) is assembled first and attached to
Definition
PRPP.
Term
What is the major regulatory step?
Definition
Formation of carbomyl phosphate
Term
UTP can lead to formation of
Definition
TMP or CTP?
Term
Carbamoyl phosphate synthase II takes place where?
Definition
cytoplasm
Term
Where does the nitrogen come from in CPSII?
Definition
Glutamine as opposed to ammonia in urea cycle.
Term
orotate condenses with PRPPto form orodylate. A decarboxylation reaction leads to
Definition
UMP, can eventually be used for RNA
Term
UTP, glutamine, and ATP react to form
Definition
CTP
Term
Where does regulation occur?
Definition
Carbamoyl phosphate synthetase II
Term
What regulates CPSII?
Definition
PRPP unregulates, ATP unregulated. UTP inhibits
Term
UTP inhibits CPS II. What does UMP inhibit:?
Definition
omp formation
Term
Pyrimidine salvage is catalyzed by?
Definition
phophorlayse
Term
Pyrimidine catabolism is soluble which disease is caused by the soluble products of purine catabolism?
Definition
gout
Term
What do oncologists monitor to see if tumors are being killed off?
Definition
They monitor b-aminosobutyrate
Term
What is the electron donor for deoxyribnonucleotide formation?
Definition
NADPH the enzyme is ribonucleotide reductase.
Term
What is oxidized on RR1?
Definition
2 Sulfhydryl groups turn ribose into deoxyribose
Term
How do the electrons flow from NADPH to RR1?
Definition
Indirectly flows thru Thioredoxin reductase, Thiordoxin and finally to RR1.
Term
What inactivates/activates the activity of dntps biosynthesis?
Definition
dATP binding to allosteric sites on ribonucleotide reductase. ATP activates it.
Term
What is the one carbon donor in TMP formation?
Definition
THF. Via the enzyme thymidylate synthase
Term
What nucleotide production do you target to kill tumors?
Definition
T, the first attempt was to block one carbon transfers
Term
Fluorouracil is called the 'suicide substrate'. Why?
Definition
It blocks the active site of Thymidine synthase 'killing' the enzyme
Term
What folate analogue blocks the active site of dihydrofolate reductase
Definition
methotrexate.
Term
What is it called when a tumor that has been destroyed returns?
Definition
Relapse. Cells can become resistant to methotrexate by amplifying the gene for dihydrofolate
Term
HOw does PRPP coordinate purine and pyrimidine biosynthesis?
Definition
PRPP activates CPSII and limiters orotate phosphoribosyltrasnferase. PRPP activates amidophospribosaltransferae and is the substrate for HGPRT and APRT.
Supporting users have an ad free experience!