Metabolism III Flashcards

1
Q

hyperammonemia

A

excess NH4+ - deplete a-KG
-inhibition of TCA cycle

tx - limit protein in diet
lactulose - acidify GI tract
rifamaxin - decreased colonic ammoniagenic bacteria
benzoate - bind AAs

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2
Q

N-acetylglutamate

A

cofactor for CPS-1
-deficient - same as CPS-1 deficiency

get hyperammonemia

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3
Q

CPS-1 deficiency

A
hyperammonemia
neonate poorly regulate temp/respiration
poor feeding 
developmental delay
intellect disability
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4
Q

MC urea cycle disorder

A

OTC deficiency

-X-linked recessive

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5
Q

OTC deficiency

A

ornithine transcarbamylase

excess carbamoyl phosphate > orotic acid

see orotic aciduria, decreased BUN, hyperammonemia

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6
Q

orotic aciduria

A

megaloblastic anemia

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7
Q

AA for dopamine, NE, E

A

phenylalanine

converted to tyrosine > dopa

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8
Q

melatonin AA source

A

tryptophan

require BH4 and B6

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9
Q

AA source of NAD+

A

tryptophan

require B6

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10
Q

AA source heme

A

glycine

require B6

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11
Q

AA source GABA

A

glutamate

require B6

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12
Q

AA source nitric oxide

A

arginine

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13
Q

AA source creatinine

A

arginine

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14
Q

AA source urea

A

arginine

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15
Q

tyrosinase deficient

A

albinism

converts DOPA > melanin

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16
Q

deficient phenylalanine hydroxylase

A

PKU

converts phenylalanine > tyrosine

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17
Q

deficient tetrahydrobiopterin

A

BH4

PKU - cofactor for phenylalanine hydroxylase

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18
Q

deficient homogentisate oxidase

A

alkaptonuria

black pigment

converts homogentisic acid > maleyacetoacetic acid

19
Q

carbidopa

A

inhibit DOPA decarboxylase

20
Q

cortisol

A

stimulate phenelethanolamine-N-methyltransferase

convert NE > E

21
Q

phenylketonuria

A

PKU

deficient phenylalanine hydroxylase
or deficient tetrahydrobiopterin (BH4) - cofactor

auto recessive

musty body odor

excess phenylketones in urine

22
Q

phenylketones

A

phenylacetate, phenyllactate, phenylpyruvate

-in urine of pt with PKU

23
Q

aspartame

A

artificial sweetener

contains phenylalanine

should be avoided PKU

24
Q

tx PKU

A

restrict phenylalanine in diet

also - supplement tyrosine (bypass enzyme deficiency)

25
Q

maple syrup urine disease

A

deficient a-ketoacid DH

cannot break down branched chain AAs
-leucine, isoleucine, valine

urine smells of burnt sugar

auto recessive

26
Q

restricted AAs in maple syrup urine disease

A

no branched chain AAs
-leucine, isoleucine, valine

also - thiamine supplementation

27
Q

alkaptonuria

A

deficiency homogentisate oxidase
-pigment forming homogentisic acid accumulate

auto recessive

dark CT, brown sclera, urine black after exposure to air

28
Q

homocystinuria

A

auto recessive

3 types:
1 -cystathione synthase deficiency
-tx decreased methionine, increased cysteine, B12, folate

2 -decreased affinity cystathione synthase for pyridoxal P
-tx vit B6 and cysteine

3 -homocysteine methyltransferase deficiency
-tx methionine in diet

29
Q

clinical homocystinuria

A
elevated homocysteine in urine
intellect disability
osteoporosis
marfanoid habitus
kyphosis
lens subluxation
thrombosis
atherosclerosis
30
Q

cystinuria

A

auto rec

defect renal PCT
-and intestinal AA transporter

of cysteine, ornithine, lysine, arginine (COLA)

31
Q

COLA

A

defective transport in cystinuria

cysteine
ornithine
lysine
arginine

32
Q

hexagonal kidney stones

A

cystinuria

33
Q

tx cystinuria

A

urine alkalinization - potassium citrate, acetazolamide

chelating agent - penicillamine

34
Q

diagnosis of cystinuria

A

urinary cyanide-nitroprusside test

35
Q

cystine

A

2 cysteine - connected by disulfide bond

36
Q

glucagon regulation of glycogen

A

activate adenylate cyclase
> increased cAMP
> increased protein kinase A
> activation glycogen phosphorylase kinase
> increased activity glycogen phosphorylase
> breakdown glycogen to glucose

37
Q

epinephrine regulation of glycogen - beta receptors

A

activate adenylate cyclase
> increased cAMP
> increased protein kinase A
> activation glycogen phosphorylase kinase
> increased activity glycogen phosphorylase
> breakdown glycogen to glucose

38
Q

epinephrine regulation of glycogen - alpha receptors

A

release of Ca from endoplasmic reticulum
> activation glycogen phosphorylase kinase
> increased activity glycogen phosphorylase
> breakdown glycogen to glucose

39
Q

insulin regulation of glycogen

A

tyrosine kinase receptor dimerize
> active protein phosphatase
> activate glycogen synthase
> more glucose to glycogen

40
Q

glycogen branches

A

a-1,6

41
Q

glycogen linkages

A

1-1,4

42
Q

glycogenolysis

A

glycogen > glucose 1-P > glucose 6-P > ATP

43
Q

glycogen phosphorylase

A

liberates glucose 1-P from glycogen

44
Q

debranching enzyme

A

4-a-D glucanotransferase - when 4 glucose on branch - transfer 3 to the long chain

a-1,6 glucosidase - when 1 glucose on branch (after 4-a-D) - breaks it off to release glucose 1-P