Nucleotide metab

Question 1

What is used for Purine Nucleotide sythesis that comes from the Pentose Phosphate Pathway?

Answer 1

Ribose sugar

Ribose 5-phosphate

Question 2

NADH generally helps with _____, while NADPH helps with___.

Answer 2

breakdown, prod. of TCA, drives ATP, Catabolic processes

bulding things, from pentose phosphate pathway

Question 3

What enzyme does Methotrexate inhibit?

Answer 3

DHFR, in the oxidation of NADPH by DHRF

Question 4

How does our body balance the amount of Adenine, Thiamine, Guanine, Cytosine?

Answer 4

Feeback and Cross reg. during PURINE nucelotide synth.

IMP, AMP, GMP, products of this pathway, INHIBIT the main guy PRPP’s synth.

Question 5

Phases of Pyrimidine Nucl. synth?

Answer 5

Phase 1: fabricate orotate ring
Phase 2: Attach PRPP to form UMP
Phase III: Convert UMP to uridine, cytosine, thymidine (doexy)nuleotides

Question 6

Phases in Purine Synthesis?

Answer 6

1. Ribose-5P activation (which comes from PPP)
2. Convert PRPP to PRA
   * *3. Construct IMP ring
   * *4. Convert IMP to adenosine and guanosine (doxy)nucleotides

Question 7

Acyclovir

Answer 7

terminates DNA replication (lacks 3’-OH group, terminator)
treats sores for Herpes, Chicken pox
Thymidine kinase has more affinity for acyclovir

Question 8

_____ + _____ = Uric Acid

Answer 8

GMP + AMP eventually in PURINE nucl. catabolism make Uric Acid

Question 9

What molecule is inhibited to help with gout pts? What enzymes does this affect?

Answer 9

Allopurinol, which affects xanthine oxidase, lowering teh number of xanthine to Uric Acid.

Question 10

Why does uric acid, but not it’s intermediates before it during Nucl. catabolism cause gout?

Answer 10

It has 3 oxygens

less water soluble (incr. solubility in joint)

Question 11

three endproducts of pyrimidine nucl. catabolism?

Answer 11

Malonyl CoA, ketogenic

**Beta-aminoisobutyrate (from dTDP and dTTP) make
methylmalonyl CoA
Succinyl CoA
both glucogenic

Question 12

sources of atoms in Purine bases

Answer 12

CO2, Gln, Gly, Asp, N10-formyl THF

Question 13

pyrimidine atom sources

Answer 13

HCO3-, Gln, Asp, N5-methylene THF

Question 14

What comes before ATP, GTP (RNA) and dATP, dGTP(DNA) during purein ring synth?

Answer 14

IMP

It is converted to AMP or GMP

Question 15

Commited step in purine synthesis?

Answer 15

• fomration of phosphoribosyl amine
  glutamine: phosphoribosyl pyrophosphate amidotransferase

pushed forward from PRPP, the molecule jus the step before via positive feedforward

Question 16

During what stage of ____ synthesis does Methotrexate attack?
What vitamin does it look very similar to?

Answer 16

Phase III: IMP ring contstruction
Purine ring

B9, folic acid. Competative inhibitor for enzymes taht use folate

Question 17

Methotrexate prevents ____ of NADPH by ___.

Answer 17

oxidation

DHFR

Question 18

Sulfa drugs work by___.

Answer 18

Being a competative inhibitor for PABA, the intermeidate for folate synth.

Question 19

PRPP is inhibited on both sides by ___, the end products of purine nucleotides.

Answer 19

IMP, AMP, GMP

Accumulation of its own endproducts inhibits its own synth.

Question 20

How are the number of Gs and As balanced?

Answer 20

In Purine synth, AMP synth. stimulated by GTP, and vise versa GMP synth is stimulated by ATP, to ensure they’re balanced and made enough equally

Question 21

Salvage pathway enzymes

Answer 21

HGPRT

APRT

Question 22

Commited step of pyrimidine synth

Answer 22

Carbamoyl Phosphate Synthase II

The first step

Question 23

What phase does the anticancer drug 5-fluorouracil (Adrucil) work?

Answer 23

phase 3: convert UMP to uridine, cytosine, thymidine deoxynucleoties

Blocks** thymidylate synthase* which stops DNA production in cancer

Question 24

**two regulatory points of pyrimidine synthesis

Answer 24

1. carbamoyl phosphate synthetates
   inh. by UMP and Purines(end product), stim. by PRPP(
2. Aspartate transcarbamoylase (ATCase)
   Feedback inh. by CTP (endproduct)

Question 25

Ortic Aciduria is an issue in what phase of pyrmidine synth?

Answer 25

Phase 2: attach PRPP to form UMP Issue with UMP Synthase Buld up of Oric acid in urine, it cant be converted to UMP

Question 26

Acyclovir works by resembling a guanine analogue that the virus has a higher affinity for. what happens then?

Answer 26

it's helps treat herpes and chicken pox cores bc. DNA polymerase cannot use the DNA bc its a fake nucelotide Viral supression

Question 27

Purine synth happens in the ____ while pyrimidine synth happens in the ____.

Answer 27

cytosol cytosol and mitochondira

Question 28

enzymes needed for nucleotide degradtion

Answer 28

"Racing Phor New Nuceotides" 1. ribonucleases and deoxyribnucleases (conver RNA/DNA to short oligomers 2. Phosphodiesterases: convert short oligomers to NMPs or dNMPs 3. Nucleotidases: NMPs/dNMPs to nucleosides and deoxynucleosides 4. Nucleosidases: remove ribose gorup, conver to pyrimidiens, purines

Question 29

AMP and GMP break down to __

Answer 29

Uric Acid

Question 30

Allopurinol inhibits Hypoxanthine and xanthine from turning into Uric acid. These two molecules build up, yet the drug helps with Gout. How?

Answer 30

Uric Acid has 3 oxygens making it less water soluble, more gout causing. Xanthine 2, and hypoxanthine have only 1 Oxygens and are more water soluble Monosodium Urate (MSU) crystals "disease of the wealthy" from wine and protein rich food

Question 31

AMP to IMP to Inosine to ___ to Xanthine to ___

Answer 31

hypoxanthine | uric acid

Question 32

ADA deaminase does what? what happens if its too much or too little?

Answer 32

adenosine homeostatis, breaks down adenosine form food too much: hemolytic anemai, premature destruction of RBC too little: SCID, severe combined immunodeficiency

Question 33

End products of pyrimidine catabolism?

Answer 33

malonyl CoA MEthylmalonyl CoA Succinyl CoA

Question 34

Pyrimidine salvage pathyway step taht acyclovir inhibits?

Answer 34

thymidine kinase, not dTMP production

Question 35

PRPP =

Answer 35

phospho ribosyl pyrophosphate

Question 36

Lesch Nyhan syndrom is from a default in the ___ enzyme in the ___ salvage pathway.

Answer 36

HGPRT Purine overproduction of uric acid

Question 37

Committed step in purinidine synth?

Answer 37

First step, | Carbamoyl phosphate synthetade II

Question 38

Anti cancer for pyrimidine synth?

Answer 38

Adrucil Aka 5-Fluorouracil Stops dna production