Purine And Pyrimidine 2

Front 1

What is the enzyme in the committed step for purine synthesis?

Back 1

Glutamine phosphoribosyl amidotransferase

Front 2

How does caffeine work?

Back 2

It is a competative inhibitor of adenosine, which has inhibitory effects on the CNS

Front 3

Most de novo synthesis of purines occurs in what ogan?

Back 3

Liver

Front 4

How many high energy bonds does purine synthesis require?

Back 4

6

Front 5

How many enzymes use ATP in purine sythesis?

Back 5

4

Front 6

What is the first purine nucleotide in the synthesis of purines?

Back 6

Inosine Monophosphate (IMP)

Front 7

The base of IMP is what?

Back 7

hypoxanthine

Front 8

What is the key enzyme in the purine salvage pathway?

Back 8

hypoxanthine-guanine phosphoribosyltransferase

Front 9

Name a cell type where the salvage of bases is the major form of nucleotide generation.

Back 9

lymphocytes

Front 10

Deficiency in purine nucleoside phosphorylase (PNP) can lead to what?

Back 10

Immunodeficiency disease, specifically T cell immunity is compromised

Front 11

Lesch-Nyhan Syndrome is caused by deficiency in what enzyme?

Back 11

HGPRT for example inhibition of Guanine to GMP

Front 12

What can treat Lesch-Nyhan Syndrome?

Back 12

Allopurinol

Front 13

What happens with adenosin deaminase deficiency?

Back 13

Severe combined immunodeficiency disease (SCID)

Front 14

Deficiency of AMP deaminase in muscle results in what?

Back 14

Muscle fatigue during exercises

Front 15

What muscle specific enzyme can create ATP directly from ADP?

Back 15

myokinase

Front 16

What is CAD in reference to the synthesis of pyrimidines?

Back 16

First three enzymes are located on the same polypeptide (carbamoyl phsophate synthetase II, Asp transcarbamoylase, and Dihydro-orotase

Front 17

Deficiency of the second enzyme (ornithine transcarbamoylase) of the urea cycle can lead to what by passing CPSII?

Back 17

orotic acidemia

Front 18

Deficiency of UMP synthase, which takes ortic acid to UMP, does what?

Back 18

Blocks pyrimidine synthesis, DNA replication doesn't work and leads to growth retardation; also cause ortic aciduria

Front 19

How do you treat UMP syntase deficiency?

Back 19

treat with oral administration of uridine: uridine converted to UMP bypassing the metabolic block

Front 20

What anticancer drug inhibits dihydrofolate in DNA synthesis

Back 20

Methotrexate and 5-fluorouracil (5-FU)

Front 21

Do we rely on the slavage pathway of pyrimidines much?

Back 21

No

Front 22

What enzymes is used to reduce ribose to deoxyribose?

Back 22

ribonucleotide reductase

Front 23

What activates ribonucleotide reducatase and inactivates it?

Back 23

ATP activates the enzyme and dATP inhibits

Front 24

High levels of dTTP we get…?

Back 24

Promtoes conversion of GDP to dGDP and promotes ADP to dADP and then get elevated dATP, which inhibits the enzyme

Front 25

ATP inhibits or stimulates production of deoxyribonucleotides?

Back 25

Stimulates and dATP inhibits

Front 26

Degradation of purines occure in what organ?

Back 26

liver

Front 27

Xanthine is converted to uric acid with what enzyme

Back 27

Xanthine oxidase

Front 28

xanthine oxidase also converts what before uric acid?

Back 28

it converts hypoxanthine to xanthine before uric acid

Front 29

Guanine to Xanthine uses what enzyme?

Back 29

Guanase

Front 30

What two enzymes make xanthine?

Back 30

Guanase and xanthine oxidase

Front 31

Urate is also used as an antioxidant?

Back 31

yes

Front 32

Two causes of accumulation of uric acid

Back 32

overproduction or malsecretion

Front 33

What in inhibits of xanthine oxidase?

Back 33

Allopurinol

Front 34

Why limit use of alcohol with gout?

Back 34

Alcohol increases the use of ATP and leads to high degradatin of purines

Front 35

Hereditary orotic aciduria is caused by what?

Back 35

UMP syntase and you accumulate orotic acid and get growth retardation

Front 36

What is UDP-glucuronic acid involved in?

Back 36

Bilirubin conjugation, synthesis of polysaccharides and oligosaccharide chains of glycoproteins

Front 37

What coenzymes Is Adenosine a core element of?

Back 37

NAD, FAD, CoA, ATP, GTP, etc.

Front 38

What inhibits CPS II?

Back 38

UTP

Front 39

What drug inhibits thymidylate synthase?

Back 39

5-fluorouracil

Front 40

What drug inhibits dihydrofolate reductase?

Back 40

Methotrexate

Front 41

What are the byproducts of pyrimidine degradation?

Back 41

NH4+, beta-alanine, CO2, B-aminoisobutyrate

Front 42

What converts bases to their nucleosides in pyrimidine salvage?

Back 42

nucleoside phosphorylase

Front 43

What conversts nucleosides to nucleotides in pyrimidine salvage?

Back 43

specific nucleoside kinases

Front 44

Thymine phosphorylase does what?

Back 44

It adds a deoxyribose resideu to make Thymidine (nucleoside) in pyrimidine salvage

Front 45

Reduction of ribose to deoxyribose occurs at what level of nucluotides?

Back 45

At the diphosphate level

Front 46

Ribonucleotide reductase has how many allosteric sites?

Back 46

Two

Front 47

Ribonucleotide reductase requires what addition enzyme with what cofactor?

Back 47

thioredoxin reductase and NADPH

Front 48

What is an attack treatment of gout?

Back 48

NSAIDs, such as ibuprofen or injection of glucocorticoids into joints