Purine Synthesis and Degradation

Question 1

what is on a nucleoside?

Answer 1

base and sugar

Question 2

what is on a nucleotide?

Answer 2

base sugar and phosphate group

Question 3

common name endings for nucleosides

Answer 3

• dine

- sine

Question 4

What do you need to start purine synthesis?

Answer 4

ribose-5-phosphate and ATP

Question 5

Where do we get ribose-5-phosphate from to start the purine synthesis?

Answer 5

from the pentose phosphate pathway

Question 6

What is the first step of purine synthesis?

Answer 6

turning ribose-5-phosphate into 5-phosphoribosyl-1-pyrophosphate (PRPP)

Question 7

What is the enzyme that turns ribose-5-phosphate into PRPP?

Answer 7

PRPP synthetase

Question 8

What inhibits PRPP synthetase?

Answer 8

nucleotides…if you have a lot you do not need to be making more

Question 9

PRPP sythetase disorder name

Answer 9

Arts syndrome….low numbers of nucleotides

Question 10

What is the committed step of purine synthesis?

Answer 10

adding an amine to the PRPP molecule to make 5-phosphoribosyl 1-amine

Question 11

What is the enzyme that turns PRPP into 5-phosphoribosyl-1amine?

Answer 11

glutamine phosphoribosyl amidotransferase

Question 12

What molecules help build the purine ring?

Answer 12

amino acids, CO2 and THF

Question 13

What molecule activates and what molecule inhibits the glutamine phosphoribosyl amidotransferase?

Answer 13

PRPP activates and nucleotides inhibit

Question 14

What is the precursor for AMP and GMP?

Answer 14

IMP

Question 15

How do we make sure we make even amounts of AMP and GMP?

Answer 15

AMP and GMP crossregulate each others enzymes that use IMP

Question 16

What enzyme does mycophenolate attack to inhibit GMP synthesis?

Answer 16

IMP dehydrogenase

Question 17

What enzyme turns AMP into ADP?

Answer 17

Adenylate kinase

Question 18

What enzyme turns GMP into GDP?

Answer 18

Guanylate kinase

Question 19

What enzyme turns ADP and GDP into ATP and GTP?

Answer 19

nucleoside diphosphate kinase

Question 20

What does degradation of purines lead to?

Answer 20

Xanthine and then uric acid

Question 21

What happens if you have too much purine degradation leading to hyperuricemia?

Answer 21

GOUT

Question 22

allopurinol

Answer 22

drug for treatment of hyperuricemia

Question 23

Adenosine initially gets broken down into what molecule?

Answer 23

Inosine

Question 24

What are the two enzymes that can make adenosine into inosine?

Answer 24

AMP deaminase and adeonsine deaminase

Question 25

What happens if you have adenosine deaminase deficiency?

Answer 25

leads to accumulation of the adenosine and deoxyadenosine molecules…deoxyadenosine is toxic

SCID

Question 26

What enzyme makes IMP into AMP?

Answer 26

adenylosuccinate synthetase

Question 27

What enzymes makes IMP into GMP?

Answer 27

IMP dehydrogenase