Lecture 4: Amino Acid Metaboism Flashcards Preview

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Flashcards in Lecture 4: Amino Acid Metaboism Deck (26):
1

What amino acids are ketogenic only?

Leu and Lys

- Leu can go to both acetoacetate and acetyl CoA, Lys can just go to acetoacetate

2

What are Ketogenic amino acids precursors for?

Ketone bodies and fatty acids

3

Where does the formation and degradation of ketone bodies occur?

Liver

4

What amino acids are both ketogenic and glucogenic?

Ile, Trp, Phe, Tyr, Thr

5

What TCA intermediate can Glu be converted to?

Alpha ketoglutyrate

6

What TCA intermediate do Phe and Tyr get converted to?

Fumarate

Phe -> Tyr -> Fumarate

7

Where is the major location of Transaminase reactions, specifically ALT and AST?

Liver and the muscle

- If these organs were to be diseased these enzymes would make it into the blood -> this can be diagnostic for liver or muscle (skeletal and cardiac)

8

What amino acids is alanine aminotransferase responsible for transaminating?

Pyruvate + Glutamate -> Alanine + Alpha ketoglutarate

9

What amino acids is aspartate aminotransferase responsible for transaminatiing?

Oxaloacetate + glutamate -> Aspartate + alpha ketoglutarate

10

What amino acid is an important carrier for Ammonia?

Glutamate/glutamine

- Ammonia is toxic to neuro tissue so glutamate ability to pick up ammonia is a protection mechanism. In the liver it will be trapped in urea and excreted in the kidney it will be trappped in urine

11

What causes homocystinuria?

1) Cystathionine beta synthase defect
2) Vitamin deficiencies (B6, 12, folic acid)

12

What are the branched chain amino acids?

Leu, Val, Ile

- They are hydrophobic and all essential

13

What causes maple syrup urine disease?

Decreased branched chain alpha-keto acid dehydrogenase complex (BCKD) activity

- Maple syrup urine disease is autosomal recessive

14

What is the hallmark maple syrup smell in newborns with maple syrup urine disease?

Branched-chain ketoaciiduria

15

How is maple syrup urine disease treated?

Synthetic diet low in BCAAs and BCKD activity can be restored with thiamine supplementation in mild forms

16

What causes Phenylketonuria (PKU)?

Defects in PAH activity -> The enzyme that converts Phe to Tyr

17

What is the most common inborn error of metabolism?

PKU

18

What causes albinism?

Tyrosinase defect causing a lack of melanin

19

How is hyperthyroidism treated?

With drugs that block iodination of thyroglobulin -> this decreases the production of thyroid hormones T4 and T3

20

Pyridoxal 5' phosphate, folic acid and vitamin B12 all may help lower what?

Homocysteine levels

21

Where are urea cycle enzymes located?

Liver

22

Ammonia is removed as _____ from the brain

Gln

23

Nitrogen is removed as _____ from muscle

Ala

24

Urea secreted in urine from __________

Kidney

25

What is the most at risk organ in the accumulation of ammonia?

Brain

26

Is NH3 or NH4 more toxic?

NH3 is the toxic agent due to its ability to permeate membranes