M1-C1-L67 --> Nucleotide Metabolism I

Front 1

Name this shit!

Back 1

Answers

Front 2

For purine synthesis, what do we need to start out with?

Back 2

PRPP (5-phosphoribosyl 1 pyrophosphate)

Front 3

How do you make PRPP?

Back 3

From Ribose 5 phosphate of the Pentose phosphate pathway and use the enzyme PRPP synthetase.

Front 4

What is the first committed step of purine synthesis?

Back 4

PRPP becomes 5-phosphoribosylamine with the help of glutamine-PRPP amidotransferase.

Front 5

In purine synthesis, what is the first purine made?

Back 5

Inosine

Front 6

From Inosinate (IMP), what is used for AMP synthesis?

Back 6

GTP

Front 7

From Inosinate (IMP), what is used for GMP synthesis?

Back 7

ATP

Front 8

IMP is the precursor for what? x 2

Back 8

AMP and GMP

Front 9

If ATP is higher than GTP, more IMP will be converted to what?

Back 9

GMP

Front 10

If GTP is higher than ATP, more IMP will be converted to what?

Back 10

AMP

Front 11

Reciprocal use of GTP and ATP does what?

Back 11

Equilibrates AMP and GMP synthesis

Front 12

What regulates PRPP and how?

Back 12

AMP, GMP, and IMP in an inhibitory manner

Front 13

What regulates Glutamine PRPP amidotransferase and how?

Back 13

AMP, GMP, and IMP in an inhibitory manner

Front 14

What regulates adenylosuccinate synthetase?

Back 14

AMP in an inhibitory manner

Front 15

What regulates IMP dehydrogenase?

Back 15

GMP in an inhibitory manner

Front 16

Answer this!

Back 16

Answers

Front 17

In pyrmidine synthesis, what do you need to start out wtih and how do you make it (enzyme and reactant)

Back 17

You need Carbamoyl phophate made from glutamine and carbamoyl synthetase II.

Front 18

Where is carbamoyl phosphate made?

Back 18

cytosol

Front 19

Carbomoyl synthetase I - where is it, what does it do, and act in what cycle?

Back 19

In mitochondria and utilizes NH4 as a nitrogen source.

Also seen in Urea cycle

Front 20

What is the first committed step of pyrimidine synthesis?

Back 20

Carbamoyl Phosphate + Aspartate ---> N-Carbamoylaspartate

Use of Aspartate transcarbamolyase

Front 21

What is CAD?

Back 21

A multifunctional trimer enzyme that is:
1. Carbamoyl Synthetase II
2. Aspartate transcarbamoylase.
3. Dihydroorotase

Front 22

What does dihydrooratase catalyze?

Back 22

N-carbamoylaspartate to dihydroorotate. (RING CLOSURE)

Front 23

What happens to dihydroorotate?

Back 23

Diffuses to mitochondria where it is oxidized by dihydroorotate dehydrogenase in to orotate.

Front 24

What happens to orotate?

Back 24

Orotate and PRPP (with the enzyme Orotate phophoribosyl transferase) is converted into Orotidylate.

Front 25

What happens to orotidylate?

Back 25

Orotidylate with the help of orotidylate decarboxylase becomes UMP (uridylate)

Front 26

What happens to UMP?

Back 26

Kinase acts on it to become UTP

Front 27

Describe the character of orotate phosphoribosyl transferase AND orotidylate decarboxylase.

Back 27

They are on the same damn enzyme.

Front 28

What happens to UTP?

Back 28

UTP becomes CTP with the help of Cytidylate synthetase, glutamine, and ATP

Front 29

How is Carbamoyl Synthetase II regulated?

Back 29

ATP and PRPP activate it
UTP and CTP inhibit it

Front 30

What does UMP regulate?

Back 30

Inhibits OMP

Front 31

A rare example occurs where the first commited step is not the regulated step. Why?

Back 31

Because carbamoyl phosphate is made in the Urea cycle.

Front 32

What is oroticaciduria type I?

Back 32

A defect in the orotate phosphoribosyltransferase AND orotidyl decarboxylase.

Front 33

What is oroticaciduria type II?

Back 33

A defect in the orotidyl decarboxylase

Front 34

What are the symptoms of patients with oroticaciduria?

Back 34

Anemia, and high levels of orotate accumulation.