Test 2: Protein Metabolism Flashcards

1
Q

How many AA are needed for gluconeogenesis?

A

18

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2
Q

What two proteins cannot be used for gluconeogenesis?

A

leucine and lysine***

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3
Q

If the liver is not functioning properly, ammonia will _______ and urea will _______.

A

increase, decrease

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4
Q

What is the rate limiting enzyme of the urea cycle?

A

carbamoyl phosphate synthetase 1 (EC 6, 3, 4, 16)***

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5
Q

About ____% of urea is filtered and the rest is reabsorbed at the distal tubule.

A

40-50

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6
Q

What is the principle of the biuret test?

A

copper binds to peptide bond to measure AA

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7
Q

What is the alpha carbon?

A

the carbon connected to the functional group

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8
Q

a protein is an amino acid chain that consists of more than ____ peptides.

A

100

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9
Q

What makes a peptide bond?

A

NH2 group linking the w/
COOH group of another,
forming a peptide bond.

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10
Q

What are the essential AA?

A

: Histidine (His), Isoleucine (Ile), Leucine (Leu), Lysine (Lys), Methionine (Met),
Phenylalanine (Phe), Threonine (Thr), Tryptophan (Trp), Valine (Val)

9 in total

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11
Q

pH at which overall net charge is neutral and the proteins stops moving

A

Isoelectric point (pI)

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12
Q

AA: equal # of opposing charge
Ionizable group at physiological pH of ____

A

7.4

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13
Q

Protein synthesis is used to make what types of proteins?

A
  • plasma proteins
  • Intracellular proteins
  • Structural proteins
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14
Q

Non Protein Nitrogen compound synthesis includes…

A

Purine, Pyrimidine, porphyrins, Creatine, Urea, Histidine, Thyroxine, Epi, Coenzyme NAD+

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15
Q

Amino acids are used for ____% of the total energy supply.

A

12-20

this energy substrate is not as good as fat or glucose

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16
Q

Pyruvate is an intermediate in the conversion of what amino acids to acetyl-CoA?

A

threonine, glycine, Serine, Cysteine, and Alanine (catabolic pathway)

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17
Q

The catabolic pathways of what amino acids are long and complex?

A

lysine, tryptophan, phenylalanine, tyrosine, and leucine

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18
Q

The catabolic pathways of what amino acids eventually get converted to alpha-ketoglutarate?

A

Arginine, proline, Histidine, Glutamine, and Glutamate

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19
Q

-Propionyl-CoA and L-methylmalonyl-CoA are intermediates in conversion of these amino acids to succinyl-CoA
-Methylmalonyl-CoA mutase is a vitamin B12 requiring enzyme

A

catabolic pathways of Methionine, Isoleucine, and valine

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20
Q

What are the metabolic disorders of amino acid metabolism? (most are genetic)

A

-Phenylketonuria
-Tyrosinemia
-Alkaptonuria
-Maple syrup urine disease (MSUD)
-Isovaleric acidemia
-Homocystinuria
-Cystinuria

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21
Q

Inborn error of “PHENYLALANINE” METABOLISM

A

Phenylketonuria (PKU)

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22
Q

what prevents the conversion to tyrosine with PKU?

A

Defective phenylalanine hydroxylase*

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23
Q

PKU causes the accumulation of…

A

phenylalanine/phenylpyruvic acid (phenylketone)

Can lead to severe metabolic acidosis & neurological problems (effects dopamine)
■ Can be controlled by monitoring diet

24
Q

How is anion gap calculated?

A

sodium - (chloride + bicarbonate)

25
Q

Inherited disorder that leads to tyrosine accumulation.

A

Tyrosinemia

26
Q

what causes Tyrosinemia?

A

Loss/defect in enzyme that catabolizes tyrosine in liver —> build up of tyrosine

27
Q

Which Tyrosinemia is the most severe?
What causes it?

A

Type 1

decreased levels of fumarylacetoacetate hydrolase

28
Q

What are the symptoms of type 1 Tyrosinemia?

A

failure to thrive, jaundice, cabbage-like odor, nose bleeds (weak capillaries)*
liver & kidney failure, neuropathy & hepatic tumors

29
Q

(rare) deficiency of tyrosine aminotransferase.

A

Type 2 Tyrosinemia

30
Q

What are the symptoms of type 2 Tyrosinemia?

A

Excessive tearing, photophobia, eye pain, lesions and mental retardation

31
Q

(very rare) Deficiency of 4-hydroxyphenylpyruvate dioxygenase

A

Type 3 Tyrosinemia

32
Q

What are the symptoms of type 3 Tyrosinemia?

A

mild retardation, seizures and intermittent ataxia

33
Q

What is known as “Black urine” or “black bone” disease?

A

Alkaptonuria

34
Q

What causes Alkaptonuria?

A

Defect in homogentisate oxidase

35
Q

What happens physiologically with Alkaptonuria?

A

-Increased homogentisic acid (HGA) - intermediate breakdown product
-HGA deposits in connective tissue, cartilage, & skin and heart - darkening of skin, urine and arthritis

36
Q

Rare genetic condition that causes urine to turn black when exposed to air,
kidney and prostate calculi, and heart problems

A

Alkaptonuria

37
Q

What causes dopamine to be effected with PKU?

A

Phenylalanine cannot be converted tyrosine to make L-DOPA —> dopamine

38
Q

What are the three branched chain amino acids (BCAAs)?***

A

valine
isoleucine
leucine

39
Q

Disorder that involves a defect in α-ketoacid dehydrogenase.

A

Maple syrup urine disease

40
Q

Maple syrup urine disease:

individual cannot properly break down …

A

the BCAAs (Val, Ile, Leu)

-Leads to an accumulation of the BCAAs & their respective keto-acids

41
Q

What are the symptoms of Maple syrup urine disease?

A

-Poor feeding, vomiting, lethargy, seizures, and developmental delays.
-Urine has a characteristic “maple syrup” odor to it.

42
Q

Rare disorder involved in the proper catabolism of leucine

A

Isovaleric acidemia

43
Q

Isovaleric acidemia leads to increased _____________.

A

isovaleric acid

44
Q

Isovaleric acidemia:

Defect in what enzyme?

A

isovaleryl-CoA dehydrogenase (IVD) enzyme

45
Q

What are the symptoms of Isovaleric acidemia?

A

Poor feeding, sweaty feet, vomiting, lethargy, and progress to coma

46
Q

What causes the distinctive odor of sweaty feet in Isovaleric acidemia?

A

Increase in isovaleric acid

47
Q

Inherited disorder involving cystathionine β-synthase (CBS) **accumulation of homocysteine & methionine

A

Homocystinuria

48
Q

What are the two cysteine disorders?

A

-Homocystinuria
-Cystinuria

49
Q

Individual cannot properly metabolize methionine/homocysteine

A

Homocystinuria

50
Q

What are the symptoms of Homocystinuria?

A

lens dislocation in eye, increase in blood clots, skeletal abnormalities, &
learning problems.

51
Q

Condition characterized by build up of cysteine caculi in kidney & bladder
■ as a result of inability to reabsorb cysteine

A

Cystinuria

52
Q

Is Cystinuria caused by a defective metabolic pathway?

A

NO

53
Q

Cystinuria:

Inherited disorder of cysteine transport ___________ (SLC3A1 or SLC7A9)
■ Defect in the transport of cysteine back in to the body

A

proteins (not enzymes)

54
Q

What is an enzyme that does the same action as Methionine synthase?

A

Homocysteine
Methyl transferase

(Homocysteine —-> Methionine)

55
Q

Conversion of homocysteine to cystathionine is done by….

A

Cystathionine
Β-synthase (TRANSSULFULATION)

56
Q

-Glutathione mobility to cells to replenish glutathione
-important enzyme of the liver

A

Gamma glutamyl transferase (GGT)

57
Q

What can an increased GGT level signify?

A

alcohol toxicity