Amino Acid Metabolism and associated diseases Flashcards

1
Q
A
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2
Q

AA synthesis:

  • Glutamate
  • Glutamine
  • Aspartate
  • Asparagine
  • Alanine
  • Arginine
A
  • Glutamate
    • a-ketoglutarate, ammonia, NADPH, glutamate dehydrogenase
  • Glutatmine
    • glutamate, ammonia, ATP, glutamine synthetase
  • Aspartate
    • oxaloacetate, glutamate, aminotransferase
  • Asparagine
    • aspartate, ATP, glutamine, asparagine synthetase
  • Alanine
    • pyruvate, glutamate, aminotransferase
  • Arginine
    • urea cycle* argininosuccinate, argininosuccinate lyase
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3
Q

Synthesis of Proline and Ornithine starts with

A

reduction of glutamate

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4
Q

Proline functions:

A
  • Sharp angles in proteins (e.g. collagen)
  • Antioxidant (Pro-to-Glu- releases NADPH)
  • Possibly osmolyte

Enzyme deficiency causes metabolic cutis laxa syndrome, a rare skin disorder

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5
Q

the starting material for serine synthesis

serine is the starting material for

A

3-phosphoglycerate

cysteine and glycine

* Phosphoglycerate dehydrogenase

* Aminotransferase

* Phosphatase

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6
Q

THF (or H4 Folate) is tetrahydrate folate, a cofactor derived from__________

A

Vit B, FOLIC ACID

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7
Q

produces NADH (energy) and is PLP dependent. In vivo it only functions in the degradation of glycine.

A

The glycine cleavage enzyme reaction

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8
Q

Folate (Vit B9) is reduced by

Folate and Tetrahydrofolate (THF) consist of 3 groups

A

dihydrofolate reductase to form THF

  • A pteridine,
  • an amino benzoate
  • a chain of one or more glutamate residues
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9
Q

THF carries _______ groups

THF carried ____ can be at various ________

A

1-C

C; oxidation states

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10
Q

B12 or B9 (folate) deficiency/ deficiency of Cystathionine synthase

a rare methionine malabsorption disease:

A
  • Homocysteineuria, cardiovascular disease
  • Oasthouse Syndrome
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11
Q

SECONDARY METABOLITES OF Amino Acids

  • Asp
  • Cys
  • Glu
  • Gly
  • His
  • Lys
  • Met
  • Orn
  • Phe
  • Ser
  • Trp
  • Tyr
A
  • Arg
    • Urea, creatine/creatine, NO
  • Asp
    • NMDA
  • Cys
    • Taurine, Hypotaurine, PAPS, thiocysteine
  • Glu
    • GABA, GSH
  • Gly
    • Heme, Oxalate, GSH, creatine/creatinine
  • His
    • Histamine
  • Lys
    • Carnitine
  • Met
    • S-adenosylmethionine, carnitine, creatine/creatinine, spermine, spermidine, choline
  • Orn
    • Putrescine
  • Phe
    • See tyrosine
  • Ser
    • Selenocysteine, ethanolamine, choline, betaine
  • Trp
    • Kynurenine, xanthurenine, serotonin, melatonin, nicotinamide
  • Tyr
    • Dopamine, norepinephrine, epinephrine, melanin, thyroid hormones
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12
Q

Selenocysteine (SeCys) is synthesized from

A

Serine

cotranslationally produced

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13
Q

aromatic quinones (tyrosine metabolites)

A

Melanin

(contains Cu++) Deficiency of enzyme tyrosinase or Cu cause Albinism

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14
Q
A
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15
Q

a rare Parkinsonism like mental disorder- can be treated with L-dopa

A

Tyrosine hydroxylase deficiency

Tyrosinase converts tyrosine to L-Dopa normally during melanin synthesis and could compensate for Tyrosine hydroxylase deficiency for catecholamine synthesis. (But two enzymes are present in different cell types)

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16
Q

critical for neurotransmitters synthesis, and is used as drug

A

SAM

17
Q

serotonin

A
  • Neurotransmitter
  • target of CNS active dugs (Its reuptake into the neuron is the target of Prozac)
  • also vasoactive (via NO synthetase)
18
Q

Melatonin

A
  • Induces sleep
  • Regulates Circadian Rhythm
19
Q

is a small molecule neurotransmitter (like Serotonin, Epinephrine (adrenaline) and Dopamine) made by decarboxylation of histidine

A

Histamine

  • Produced in Mast Cells and basophils
  • Important part of the inflammatory response/ immune response
  • a powerful vasodialator
  • also helps regulate physiological function in the gut; sleep; and the sexual response
20
Q

Glutathione:

A
  • a reductant; e.g. protect RBCs from peroxidation? Use of GSH Peroxidase (recall selenocysteine)
  • Regenerate GSH using glutathione reductase and NADPH (from the hexose monophosphate shunt)
  • Conjugated with drugs to make them more soluble for clearance by the kidney
  • Transport of aa across membranes