Biochemistry 02 - Purine And Pyrimidine Metabolism

Front 1

What is the use of nucleotides

Back 1

Nitrogenous base + pentose monosaccharide + phosphate group, DNA, RNA, ATP, NAD, UDP-glucose

Front 2

What is the function of nucleotides in the GI?

Back 2

Mostly made denovo - only 5% taken in diet - used for synthesis of purines + pyrimidine's

Front 3

What molecule do purines build off of?

Back 3

PRPP -> built one atom at a time to make purines

Front 4

What is the rate of purine synthesis dependent upon?

Back 4

Dependent upon [PRPP] b/c PRPP concentrations are usually below Km

Front 5

What happen to purines if there is no Folate?

Back 5

U cant make purines b/c u are going to b missing 2 carbons -> thus cant make DNA

Front 6

What happens to pyrimidine's if there is no Folate?

Back 6

U cant convert U-> T thus u cant make DNA

Front 7

RR

Back 7

Ribonucleotide reductase - remove C2 on ribose ring -> converts to 2-deoxyribose -> necessary for synthesis of DNA

Front 8

Ribonucleotide reductase inhibitors = Anti-cancer drug

Back 8

Hydroxyurea = Stops DNA synthesis(slows cell growth)

Front 9

What molecule is a feed back inhibitor on ribonucleotide reductase?

Back 9

dATP - b/c u make enough nucleotides u don’t need to make more thus turn of Ribonucleotide reductoase (RR)

Front 10

Pt w/ 100x ↑ [dATP] but ↓ dTTP, ↓ dGTP, ↓ dCTP

Back 10

Adenosine deaminase deficiency = T + B cells affected - immununodeficiency(SCID)

Front 11

Pt w/ ↑ [dGTP] but blocked dCTP + dTTP

Back 11

Purine nucleoside phosphorylase deficiency = T -cells affected - immunodeficiency

Front 12

Elevated uric acid due to hypoxanthine-guanine phospho-ribosyl transferasae deficiency

Back 12

Lesch-nyhan syndrome - ↑ hypoxanthien + guanine concentrations -> ↑ uric acid b/c u cant recycle them thus the body tried to excrete them

Front 13

What drink elevates uric acid lvls?

Back 13

Beer

Front 14

What drug is used to treat elevated uric acid?

Back 14

Allopurinol - blocks xanthine oxidase -> synthesis of uric acid prevents conversion of hypoxanthine -> xanthine -> uric acid

Front 15

What are the treatments for gout?

Back 15

1. Colchicine (anti-inflammatory), 2. allopurinol (inhabits uric acid formation), 3. probenicid (inhibits kidney organic anion transporters -> blocks reabsorption of uric acid -> ↑ excretion of uric acid), 4. avoid meat, seafood, beer

Front 16

Pt w/lack of HGPRT gene

Back 16

Lesch-nyhan syndrome

Front 17

What are the problems in lesch-nyhan

Back 17

↑ PRPP -> ↑ de novo syntehsis of purines ->gout like damage to the brain -> chew on their fingers

Front 18

Treatment for lesch-nyhan

Back 18

Allopurinol

Front 19

Pt w/poorly coordinated, mentally retarted, extremely hostile, compulsive self-destructive tendencies: mutilate by biting off their fingers, toes, and lips

Back 19

Lesch-nyhan

Front 20

What bases are ↓ in orotic aciduria?

Back 20

↓ RNA bases C + U, ↓ DNA bases C + T, also causes immunodeficiency

Front 21

New born, macrocytic hypochromic megaloblastic anemia, failure to thrive, sparse hair, cardiac malforamtions, bilatreal strabismus, inability to sit unaided, Crystal urea -> kidney stones, immunodeficiency's,

Back 21

Orotic aciduria