Amino Acids Metabolism Flashcards Preview

M1 - MCM Exam 1 > Amino Acids Metabolism > Flashcards

Flashcards in Amino Acids Metabolism Deck (42):
1

Supplies for the Amino Acid Pool

  1.  Protein turnover - proteins salvaged and repurposed in the body
  2. Digested food - mostly from meat, veggies, and nuts
  3. De novo synthesis - synthesis of non-essential amino acids

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Sources that Deplete the Amino Acid Pool

  1. Production of body protein
  2. Synthesis of nitrogen-containing compounds
  3. Degradation of essential amino acids

3

Proteolytic Enzymes

Degradation of proteins for reabsorption

4

Two Classes of Proteolytic Enzymes

  • Exopeptidase - attacks the N or O terminus ends
    • Carboxypeptidase - Attacks and adds H2O at the O end
    • Aminopeptidase - Attacks and adds H2O at the N end
  • Endopeptidase - attacks within the protein at a specific site

5

Lysosomes

Performs autophagy

Contains over 50 proteolytic enzymes

Internal environment within lysosome has a pH of 5

6

Proteasome 

A large protein complex within the cells that breaks apart marked proteins

Marker - ubiquinitin

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Ubiquitin

Marker of proteins that need to be degraded within a cell

Polyubiquitinated

8

Zymogens

The inactive form that most digestive enzymes are secreted

Become active when they get to their target

Ex. Trypsinogen - activated by enterokinase after getting into small intestine lumen - becomes trypsin

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Essential Amino Acids

PVT TIM HALL

  • Phenylalanine
  • Valine
  • Tryptophan
  • Threonine
  • Isoleucine
  • Methionine
  • Histidine
  • Arginine
  • Leucine
  • Lysine

Occassionally Glutamine - depending on deficiency

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10

Ketogenic Amino Acids

Leucine and Lysine

2:5:13

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11

Ketogenic and Glucogenic Amino Acid

Isoleucine, Tryptonphan, Phenylalanine, Tyrosine, and Threonine

2:5:13

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12

Glucogenic Amino Acids

Valine, Histidine, Methionine, Glycine, Arginine, Alanine, Proline, Aspartic Acid, Serine, Glutamic Acid, Glutamine, Cysteine, Asparagine

2:5:13

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13

Why is the TCA cycle Anaplerotic?

Anaplerotic - reactions that supply intermediates for a metabolic pathway

Amino acids supply the TCA cycle with substrates if needed

Pyruvate carboxylation (requires ATP) converts pyruvate to oxaloacetate (OAA)

 

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14

Reaction that Shuffles Amine groups

Transamination

15

Enzymes that perform transamination

Transaminases/Aminotransferase

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Transaminase coenzyme

PLP (pyridoxyl-5'-phosphate)

Derivative of Vit B6

 

17

AST/ALT

Aspartate transaminase (AST) Alanine transaminase (ALT)

Used as clinical markers for liver function

18

Amino acids that are metabolized into alpha-ketoglutarate

Gln, His, Arg, Pro all converted to Glutamine

Glutamine is then converted into alpha-ketoglutarate

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19

Branched Chain Amino Acid Metabolism

Valine and Isoleucine - converted to Succinyl-CoA

Leucine - Converted to Acetyl-CoA

If deficiency causes Maple-Syrup urine disease

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20

Methionine Metabolism

Converted into Succinyl-CoA

Able to produce Cysteine

If issues in metabolism - commonly results in Homocystinuria

 

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Threonine Metabolism

Converted into Succinyl-CoA

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22

What two enzymes are responsible for Homocystinuria?

Homocysteine methyltransferase - converts homocysteine back to Methionine

Cystathionine-B-synthase - converts homocysteine into cystathionine (enzymes requires PLP (active form of B6)

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23

Hyperhomocysteinemia and Homocystinuria

Usually caused by vitamins (B6, B12, or Folic Acid (B9)) or genetic disorder

Risk factor for heart disease and stroke

Treated usually with vitamin suppliments

24

Maple Syrup Urine Disease

Deficiency in BCKD (branched-chain alpha-keto acid dehydrogenase complex)

Inability to break down branched-chain amino acids

Presents as branched-chain amino acids in urine which gives urine a sweet smell

High prevalance in Jewish, Amish, and Mennonite populations

25

Deficiency in BCKD

Maple Syrup Urine Disease

26

Phenylalanine Metabolism

Phenylalanine converted to Tyrosine then to Fumarate

27

Phenylketonuria (PKU)

Mutation or disfunction of Phenylalanine hydroylase and inability to convert Phe to Tyr

Results in accumulation of phenylpyruvate and phenyllacetate - elevated levels are toxic to CNS

Musty-odored urine

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Asparagine Metabolism

Asparagine is metabolized into Aspartic Acid then into oxaloacetate

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29

What is Aspartic Acid derived from?

Asparagine

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Tryptophan Derivatives

NAD+/NADP+ and Serotonin

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31

Tyrosine Derivatives

T3 (Triiodothyronine), T4 (Thyroxine), Melanin, DOPA, and Oopamine (synthesized into Norepinephrine and Epinephrine)

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32

What common diseases are associated with Tryosine derivatives?

Grave's Disease (Hyperthyroidism) or Hypothyroid

Albinism

Parkinsonism

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Thyroglobulin and Thyroid Hormone

Thyroglobulin produces T3 and T4

Uses tyrosine in the binding site

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34

Removing Nitrogen in Brain

As ammonia

Remove Glutamine and Glutamic acid as ammonia

CO - comes from CO2

1 NH2 - NH4+

NH2 - from aspartate

 

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Removal of Nitrogen in Muscles

In muscles combines pyruvate and glutamate to make alpha-ketoglutarate and alanine (nitrogen goes on Alanine

They excrete alanine which travels to the liver and the nitrogen is freed into ammonia and enters the urea cycle

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36

Transamination vs. Oxidative deamination

Transamination move the amino group

Aminotransferase produces ammonia

37

Urea Cycle Common Diseases

Hyperammonemia w/ orotic aciduria - malfuction of enzyme in between ornithine and citrulline

Hyperammonemia - where ammonium is unable to be incorporated into carbarnoyl phosphate

Citrullinemia - a build up of citrulline

Argininosuccinate aciduria - 

38

Ammonia Toxicity

Issue because NH3 is able to cross the blood-brain barrier

Causes pH imbalance and brain swelling

Messes with glutamate dehydrogenase to alpha-ketoglutarate becuase of the abundance of ammonia which stalls TCA cycle

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39

Amino acids associated with Phosphocreatine

Arg, Gly, and Met

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40

Location and Purpose of Phosphocreatine

Located in spern, brain and muscles

Used as a storage form of energy

41

What is creatine a biomarker for?

Kidney function

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