Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

21 fall: Biochem > lecture 6 > Flashcards

lecture 6 Flashcards

1
Q

your patient shows retarded growth, severe anemia and high levels of orotic acid in their urine (orotic aciduria)
Cause
Treatment

A

high orotate (one of the products/steps of pyrimidine production)

means either
oroate
-orotate phosphoribosyl transferase 
=orotidylate
or 
orotidylate
-orotidylate decarboxylase
UMP( uridylate)
is NOT working

Treatment: feed them pyrimidine (uridine triacetate UTP)

  • if body has pyrimidines then it doesn’t need to make pyrimidine therefore the step/products will not be produced and therefore no buildup can happen
  • end products feedback inhibit production of pyrimidines
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

canine with lymphoma
is 5-flurouracil good option?
if not what is a good option?

A

5-FU is toxic for dogs
-gastro(hypersalivation, vomiting), CNS (ataxia, seuzures) and bone marrow suppression (anemia)

Treatment: Use aminopterin (methotrexate)

-inhibits dihydrofolate reductase (dihydrofolate to tetrahydrofolate which turns into Methylenetretrahydrofolate (dUMP to dTMP))

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

called to zoo for animal with uric acid in urine and in pain
Which animal?
Treatment?

A

primate- uric acid is end product of purine degradation

treatment: ALLOPURINOL
competitive inhibitor for xanthine oxidase (enzyme used in purine deg)-
allopurinol gets attached to PRPP, lowers level of PRPP, which in turn lowers the production of biosynthesis

  • stops hypoxanthine from changing into xanthine
  • stops xanthine from turning into uric acid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

dalmatian with blood in urine

A

dalmatians have defect in liver and can not take up uric acid into liver to be converted into allantoin, therefore they can have build up in uric acid which can lead to gout.

gout can be treated will ALLOPURINOL

blocks Xanthine oxidase
uric acid is form breakdown of purines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

treatment for leshmaniasis?

A

parasite that feeds on purine from host. if you use ALLOPURINOL to reduce the amount of purines the host make, hopefully starving the parasite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what sugar does RNA use

A

ribose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what sugar does DNA use

A

deoxyribose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

pyrimidine

A

1 ring
uracil
cytosine
thymine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

purine

A

2 rings
adenine
guanine

Pure As Gold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is committed step to make purine

A

PRPP
5-phosphoribosyl-1-pyrophosphate

amidoposphoribosyl transferase
(2 phospate gets switch into amino group) (+glutamine --> glutamate)

5-phosphoribosyl-1-amine and PPi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what sugar does DNA use

A

deoxyribose

no ribose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how to make purine

A

ribose 5 phosphate

add ATP (ribose phosphate pyrophosphokinase) 2 phosphate gets added)

PRPP (5-phosphoribosyl-1-pyrophosphate)

add glutamine (2 phospate gets switched with amino group)
-amidophosphoribosyl transferase (committed step_

5-phosphoribosyl-1- amine
and PPi

bunch of steps

get purine inosinate (IMP)

inosinate (IMP) can turn into

-adenylosuccinate then ADENYLATE (AMP)
or
-xanthylate then GUANYLATE(GMP)

AMP is adenine with ribose-P added

GMP is guanine with ribose-P added

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is committed step to make purine

A

PRPP

amidoposphoribosyl transferase
(2 phospate gets switch into amino group) (+glutamine --->glutamate)

5-phosphoribosyl-1-amine and PPi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

AMP is

A

adenine with ribose-P added

IMP turns into adenylosuccinate then AMP (adenylate)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

GMP is

A

guanine with ribose-P added

IMP (inosinate) turns into Xanthylate then GMP(guanylate)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how to fix when purine rings come off sugar

A

hypoxanthine-guanine phosphoribinosyl transferase

PRPP + guanine = guanylate (GMP) + PPi

PRPP + hypoxanthine= inosinate (IMP)+ PPi

Adenine Phosphoribosyl transferase
PRPP + Adenine = Adenylate(AMP) + PPi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

explain Adenine Phosphoribosyl transferase

A

used when purine comes off sugar

PRPP + Adenine = Adenylate + PPi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

explain hypoxanthine-guanine phosphoribinosyl transferase

A

used when purine comes off sugar

PRPP + guanine = guanylate + PPi

PRPP + hypoxanthine= inosinate (IMP)+ PPi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

lesch-nyhan syndrome

what is a common symptom

A

deficiency in HGPRT

self mutilation

body cant fix when purines come off PRPP/sugar therefore there is more PRPP just floating around in the body.

PRPP causes increase in purine biosynthesis (increased purine biosynthesis).

too many purines need to be broken down. breakdown of purines creates uric acid.

20
Q

how to degrade purines in humans and primates

A 
AMP
-adenosine deaminase
IMP
-gets changed into
Hypoxanthine
-Xanthine Oxidase
Xanthine
-Xanthine Oxidase (again)
Uric acid
21
Q

how does adenosine deaminase change AMP

A

AMP changes into IMP

purine degradation part 1

AMP (adenylate) (adenine with ribose-P) (one of the products of purine synthesis)

NH2 gets switched into double bonded O

this is IMP (inosinate)

22
Q

how does xanthine oxidase change hypoxanthine

A

Hypoxanthine turns into Xanthine

purine degradation part 3

H turned into double bonded O

(oxidase means lose electron- reaction is reduced) (LEO) makes it more water soluble by added O

this is now Xanthine

23
Q

how does xanthine oxidase change Xanthine

A

Xanthine turns into Uric Acid

purine degradation part 4

H turned into double bonded O

(oxidase means lose electron- reaction is reduced) (LEO)- makes it more water soluble by added O

this is now Uric Acid

24
Q

defect in adenosine deaminase

A

enzyme for purine degradation part 1 AMP to IMP

no adenosine deaminase means no immune system (bubble boy)

25
Q

purine degradation in other animals

A 
(1st 4 steps the same)
AMP
-adenosine deaminase
IMP
-gets changed into
Hypoxanthine
-Xanthine Oxidase
Xanthine
-Xanthine Oxidase (again)
Uric acid

non primate mammals will go one step further
uric acid gets changed into allantoin

allantoin
allantoate
urea and glyoxylate (fish)
4NH4 and 2 CO2 (marine invertebrates)

26
Q

end product of purine degradation for non primate mammals

A

allantoin

uric acid + O2= allantoin

27
Q

end product of purine degradation for fish

A

urea and glyoxylate

allantoin + water= allantoate
allantoate +water=urea and glyoxylate

28
Q

end product of purine degradation for marine invertebrates

A

4NH4 and 2 CO2

urea plus water = 4NH4 and 2 CO2

29
Q

disease from too much uric acid

A

gout

30
Q

how does allopurinol work

A

competitive inhibitor for xanthine oxidase( step 3 and 4 of purine degradation)

  • stops hypoxanthine from changing into xanthine
  • stops xanthine from turning into uric acid

allopurinol attaches to PRPP, this means there is less free PRPP floating around, this means purine biosynthesis goes down

decrease in purine synthesis means there is not extra purines that need to get broken down. therefore uric acid is not being produced

31
Q

problems with allopurinol

A

allopurinol blocks xanthine oxidase meaning there can be a build up of xanthine (step from purine degradation). this buildup can be toxic

32
Q

Xanthine oxidase deficiency

treatment?

A

do not have enough xanthine oxidase (enzyme used in step 3 and 4 of purine degradation)

patient cant break down xanthine

leads to

  • xanthinuria
  • nephropathy
  • renal failure

treatment: low purine diet and fluids

33
Q

** your patient is suffering from gout-like symptoms. what treatment do you recommend? what is this treatment effective

A

allopurinol

competitive inhibitor for xanthine oxidase thus decreasing the production of uric acid

also binds to PRPP thus lowering the amount of purine synthesis. since high PRPP levels activate purine synthesis

34
Q

*** will elevated PRPP levels increase or decrease purine biosynthesis

A

increase

PRPP is first step of purine biosynthesis, would push the reaction forward

35
Q

fetal death in dairy cows can be cause by errors in ____

A 
pyrimidine metabolism
(DUMPS) deficiency of uridine monophosphate synthase
36
Q

pyrimidine biosynthesis

A

CO2 +glutamine + ATP
-carbomoyl phosphate synthetase

carbamoyl phosphate and aspartate

  • aspartate transcarbamoylase (removes Pi)
  • bunch of steps

OROTATE
-orotate phophoribosyl transferase (add orotate to PRPP)

OROTIDYLATE
-oritidylate decarboxylase (carboxyl group removed)

Uridylate (UMP) (pyrimidine!!)

UMP -nucleoside kinase= UTP (uridine triphosphate)

UTP -glutamine= CTP (cytidine triphosphate)

UTP inhibits aspartate transcarbamoylase(2nd step)
and carbamoyl phosphate synthetase (1st step)

37
Q

how to go from UMP to dTMP

A

UMP
-ribonucleotide reducatase

dUMP

dUMP+ N5N10 methylenetetrahydrofolate
-thymidylate synthase

dTMP and Dihydrofolate

TO GO BACKWARDS
Dihydrofolate
-dihydrofolate reductase

N5N10 methylenetetrahydrofolate

38
Q

UMP can change into

A

UMP- nucleoside kinase=UTP -glutamine=CTP

UMP- dUMP-dTMP

39
Q

how do you prevent thymidine production

A

inhibit dihydrofolate reductase or inhibit thymidylate sunthase

(pyrimidine synthesis)
dUMP to dTMP

40
Q

inhibition of thymidine production is a common way chemo works by

A

preventing production of thymidine which kills cell

fluorouracil
inhibits -thymidylate synthase (dUMP to dTMP)

aminopterin (methotrextate)
inhibits dihydrofolate reducatse
(dihydrofolate-methylenetetrahydrofolate)

41
Q

how is thymidylate synthase inhibited

A

fluorouracil

stops dUMP into DTMP

42
Q

how is dihydrofolate reductase inhibited

A

aminopterin and amethopterin (methotrexate)

stops dihydrofolate back into Methylenetetrahydrofolate

43
Q

what species can 5-flurorouracil be used

A

cats- but very careful with dosage

44
Q

*** in class we discussed two compounds that inhibit production of dTMP. What are these compounds and what specifically do they inhibit?

A

Fluorouracil
-inhibits thymidylate synthase
(dUMP into dTMP)

Methotrexate(aminopterin)
- inhibits dihydrofolate reductase
(dihydrofolate back into methlenetetrahydrofolate)

45
Q

Pyrimidine synthesis

A

G(CPS)A(AT)—
Oroate (OPT)=Orotidylate(OD) =UMP

Ump Uridylate
1.UMP
2. UMP-> UTP
3 UMP-> UTP-> CTP
4.UMP (RR) dUMP
dUMP + tetra (TS) -> dTMP + dihydrofolate

(go backwards)
dihydrofolate (DR) =tetra

46
Q

what is a feedback inhibitor of the pyrimidine synthesis and which step does it work?

A

UTP (uridine triphospate)

blocks step 1
glutamine +CO2 + ATP (CPS) = CP + Aspartate

step2
aspartate (AT) = bunch of steps orotate

21 fall: Biochem (44 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions