Nucleotide Synthesis

Question 1

What are the sources of the nitrogen atoms in purine synthesis?

Answer 1

Aspartate, glutamine, and glycine

Question 2

What is the parent molecule of purine synthesis?

Answer 2

Inosine monophosphate (IMP)

Question 3

What are the sources of the carbon atoms in purine synthesis?

Answer 3

Glycine, CO2, N10formyl H4 folate/ N5N10formyl THF

Question 4

What is the name of the ring that is the precursor to the purine molecules?

Answer 4

Hypoxanthine

Question 5

What is the reaction that converts ribose 5 P to PRPP (phosphoribosylpyrophosphate)

Answer 5

Ribose 5P + 4ATP + Mg2+ -> PRPP synthase –> PRPP

Question 6

What amino acid and high energy compound converts IMP to AMP?

Answer 6

Aspartate and GTP

Question 7

What amino acid and high energy compound converts IMP to GMP?

Answer 7

Glutamine and ATP

Question 8

What is the reaction and enzyme to make AMP?

Answer 8

Adenosine + PRPP -> AMP
enzyme: APRT

Question 9

What are the two reactions and enzymes to make IMP/GMP?

Answer 9

1. Hypoxanthine + PRPP -> IMP (using HGPRT)
2. Guanine + PRPP -> GMP (using HGPRT)

Question 10

Ribose 5P + 4 ATP + Mg2+ -> ?
What enzyme is used?

Answer 10

Phophoribosylpyrophosphate (PRPP)
enzyme: PRPP synthase

Question 11

Adenosine + PRPP -> ?
What enzyme is used?

Answer 11

AMP
enzyme: APRT

Question 12

Hypoxanthine + PRPP -> ?
What enzyme is used?

Answer 12

IMP
enzyme: HGPRT

Question 13

Which tissues are unable to use the salvage pathway for purine synthesis?

Answer 13

Brain, RBCs, WBCs

Question 14

Guanine + PRPP -> ?
What enzyme is used?

Answer 14

GMP
enzyme: HGPRT

Question 15

Name the water soluble molecule that is produced in purine degredation

Answer 15

Xanthine

Question 16

Name the less water soluble molecule that is produced after xanthine in purine degredation

Answer 16

Uric acid

Question 17

What enzyme converts xanthine to uric acid in purine degredation?

Answer 17

Xanthine oxidase

Question 18

What drug blocks xanthine oxidase?

Answer 18

Allopurinol

Question 19

What natural food blocks xanthine oxidase?

Answer 19

Bing cherry juice

Question 20

What is gout?

Answer 20

High levels of uric acid in blood (uricemia)

Question 21

What causes gouty arthritis?

Answer 21

Deposit of sodium urate crystals in joints (toes, hand, etc.)

Question 22

What is gout in the big toe termed?

Answer 22

Podagra

Question 23

What is the genetic predisposition for gout?

Answer 23

X-linked recessive (men)

Question 24

What foods are high in purines?

Answer 24

Organ meats, aged cheese, alcohol

Question 25

What disease is caused by the genetic enzyme deficiency of HGPRT?

Answer 25

Lesch-Nyhan syndrome (chewing of the hands and mouth)

Question 26

What are the symptoms of Lesch-Nyhan syndrome?

Answer 26

Gouty arthritis, cognitive impairment, self-mutilation

Question 27

What disease is caused by the genetic enzyme deficiency of glucose 6 phosphatase?

Answer 27

Von Gierke's disease (glucose can't leave liver)

Question 28

What are the symptoms of Von Gierke's disease?

Answer 28

Hypoglycemia, glycogen nodules, and gouty arthritis

Question 29

What is the parent molecule of pyrimidine synthesis?

Answer 29

Uracil monophosphate (UMP)

Question 30

What are the sources of the nitrogen atoms in pyrimidine synthesis?

Answer 30

Aspartate and glutamine

Question 31

What are the sources of the carbon atoms in pyrimidine synthesis?

Answer 31

CO2 and aspartate

Question 32

What are the two enzymes needed for pyrimidine synthesis?

Answer 32

CAD and UMP synthase

Question 33

What amino acid and high energy molecule is needed to convert UMP to CTP?

Answer 33

Glutamine and ATP

Question 34

What enzyme converts dUMP to dTMP?

Answer 34

N5N10 methylene THF (need methyl)

Question 35

What classification of drugs blocks dUMP conversion to dTMP?

Answer 35

Anti cancer drugs (folate inhibitors)

Question 36

What is the energy source to convert TMP to TTP?

Answer 36

ATP

Question 37

What enzyme and coenzyme converts ribonucleotides to deoxynucleotides?

Answer 37

Ribonucleotide reductase

Question 38

Are there any diseases from the degradation of pyrimidines?

Answer 38

No