Misc. Proteins Flashcards

1
Q

What three amino acids contribute to creatinine?

A

glycine, arginine and ornithine

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2
Q

Where does the nitrogen in creatinine come from?

A

guanidinoacetate

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3
Q

What is the function of creatinine phosphate?

A

energy reserve for muscles

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4
Q

Specifically, how is this accomplished?

A

creatine phosphate can phosphorylate ADP to ATP

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5
Q

How is creatinine formed?

A

self cyclization

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6
Q

Where is creatinine formed and released from?

A

muscle cells

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7
Q

What co-factor does phenylalanine hydroxylase require?

A

THBtn

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8
Q

Thyroid hormones are iodinated versions of what?

A

tyrosine

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9
Q

What is the function of thyroid peroxidase?

A

iodination of tyrosine

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10
Q

Where is thyroglobulin degraded? What does this release?

A

lysosomes

T3 and T4

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11
Q

What is the molecular function of tyrosinase?

A

converts tyrosine to DOPA and DOPA to dopaquinone

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12
Q

Where does melanin synthesis begin?

A

golgi of melanocytes

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13
Q

What is dopaquinone synthesized into?

A

melanin

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14
Q

What is the main function of melanin?

A

protect against UV radiation

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15
Q

What tissues are melanocytes found in?

A

skin and hair follicles

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16
Q

Albinism is caused by what?

A

loss of tyrosinase activity

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17
Q

What two products are derived from tryptophan?

A

serotonin and melatonin

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18
Q

What two tissues are rich in serotonin?

A

platelets and GI tract

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19
Q

What two steps are down to tryptophan to make serotonin?

A

hydroxylation and decarboxylation

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20
Q

What enzyme hydroxylates tryptophan?

A

tryptophan hydroxylase

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21
Q

What co-factor is required for tryptophan hydroxylase?

A

THBtn

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22
Q

What is the first step in the conversion of serotonin to melatonin?

A

N-acetyltransferase converts serotonin to N-acetylserotonin

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23
Q

What is the second step in the conversion of serotonin to melatonin? What does that enzyme require?

A

methylation by hydroxyindole-O-methyltransferase

SAM

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24
Q

What is the third product that tryptophan can be converted into?

A

niacin

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25
Q

What enzyme begins the synthesis of tryptophan to niacin?

A

IDO

indolamine-2,3-dioxygenase

26
Q

What is niacin synthesized from?

A

Tryptophan

27
Q

What co-factors are required for the conversion of tryptophan to niacin?

A

iron, riboflavin and pyridoxine

28
Q

What can Hartnup disease be treated with?

A

high protein diet and niacin

29
Q

What is formed by the decarboxylation of glutamate? What co-factor does this require?

A

GABA

pyridoxal phosphate

30
Q

Histamine is released by what type of cell?

A

mast cell

31
Q

What three amino acids make up glutathione?

A

glutamate

cysteine

glycine

32
Q

Why is glutathione such a stable molecule?

A

special peptide bond that is resistant to proteolysis

33
Q

What else is atypical about glutathione?

A

it is not manufactured by ribosomes

34
Q

How does glutathione act to scavenge free radicals?

A

absorbing electrons and forming a glutathione dimer

35
Q

Glutathione peroxidase contains what element?

A

selenium

36
Q

In RBCs, glutathione acts to do what?

A

reduce oxygen free radicals produced during oxygen transport

37
Q

What is the function of glutathione-s-transferase?

A

transfer glutathione to electrophiles

38
Q

What elements do these electrophiles need to attach to glutathione with?

A

Sulfur, oxygen or nitrogen

39
Q

What kind of bond is generated between glutathione and these electrophiles? Where is it located?

A

a thioether linkage between the compound and cysteine of glutathione

40
Q

What is creatine production proportional to?

A

individuals muscle mass

41
Q

Regarding catecholamine synthesis, what enzyme requires THBtn?

A

tyrosine hydroxylase

42
Q

PNMT uses what as a carbon group donor?

A

SAM

43
Q

What ion does tyrosinase contain?

A

copper

44
Q

The formation of niacin from tryptophan begins with what enzyme?

A

IDO

45
Q

Decarboxylation of histidine yields what? What co-factor does this reactio require?

A

Histamine

Pyridoxal phosphate

46
Q

What is the first enzymatic step in the production of serotonin? What co-factor does this enzyme require?

A

hydroxylation of tryptophan to 5-hydroxytryptophan

THBtn

47
Q

What are GST molecules involved in?

A

detoxification process

48
Q

What electrophiles must a compound contain to become attached to glutathione?

A

S, O, N

49
Q

In the formation of glutathione conjugates, what type of linkage is created?

A

thioether

50
Q

The overall rate of amino acid degradation is influenced by what enzyme?

A

mitochondrial glutamate dehydrogenase

51
Q

What is the activity of mitochondrial glutamate dehydrogenase dictated by? How so?

A

cellular energy charge

high energy = inhibit

low energy = activate

52
Q

How is B12 related to myelin?

A

cant degrade methylmalonyl-CoA w/o B12

odd chain fatty acids get incorporated into myelin = bad

53
Q

What is the fucntion of BCAT? Where is the majority of BCAT located?

A

to form branched-chain alpha-keto acids from branched chains AA’s

muscles

54
Q

Where are branched chain alpha keto acids degraded? What enzyme is responsible for this?

A

liver

BCKDH

55
Q

MSUD features an accumulation of what products? What is this condition caused by?

A

branched chain alpha keto acids

lack of BCKDH

56
Q

How does mannitol aid in the treatment of hyperammonemia?

A

diuresis

57
Q

What does phenylbutryate ‘pull’ out of solution?

A

glutamine

58
Q

What does benzoate ‘pull’ out of solution?

A

glycine

59
Q

Specifically, what brain structure can swell during hyperammonemia?

A

astrocytes

60
Q

Increased ammonia increases the synthesis of what amino acid?

A

glutamine