Green (Delidow) - Amino Acids

Question 1

What is formed when amino acids lose their amino groups?

Answer 1

a-Keto Acid

Question 2

Where do the amino groups head in AA degradation?

Carbon skeletons?

Answer 2

Amino groups head for biosynthetic pathways, or the urea cycle through carbamoyl phosphate

Carbon skeletons are converted to a-Keto Acids and enter the citric acid cyle

Question 3

Where does amino group catabolism occur?

Answer 3

Liver

Question 4

What does muscle send to the liver to enter amino acid catabolism?

Answer 4

Alanine, Glutamine

Question 5

What removes the amino group from AAs?

Answer 5

Aminotransferase

Transaminase

Question 6

What is the amino group usually transfered to once removed from an AA?

What does this require?

Answer 6

Transfered to a-Ketoglutarate to form glutamate

Pyridoxal Phosphate (PLP) coenzyme

Question 7

What is the most common acceptor (and eventual donor) of amino groups?

Answer 7

Glutamate

Question 8

Aside from Glutamate, what other AA can serve as aminotransferases?

Answer 8

Alanine to Pyruvate

Aspartate to Oxaloacetate

Question 9

Where does oxidative deamination occur?

What catalyzes the reaction?

Final products?

Answer 9

Mitochondria

Glutamate Dehydrogenase

a-ketoglutarate / ammonia

Question 10

What is a direct source of ammonia nitrogen for the urea cycle?

What other AA can provide the ammonia?

Answer 10

Glutamate dehydrogenase release of ammonia

Serine, threonine, glutamine

Question 11

What is the destination of the a-ketoglutarate once ammonia removed?

Answer 11

Citric Acid Cycle

Glucose Synthesis

Question 12

How is Glutamate Dehydrogenase regulated?

Answer 12

Activate: Low Energy

Inhibit: High Energy

Question 13

How is ammonia formed in muscle transported to liver?

Answer 13

Glutamine, Alanine

Question 14

Where is ammonia converted to urea?

Answer 14

Mitochondria

Question 15

What can reduced liver function (inherited or acquired) cause?

Answer 15

Ammonia Intoxication, tremors, slurred speech, blurry vision

Question 16

Where does the urea cycle occur?

Answer 16

Begins inside mitochondria, but subsequent steps take place in cytosol

Question 17

What is the first step in the urea cycle?

What does this product donate to create?

Answer 17

Ammonia and CO₂ form carbamoyl phosphate

Carbamoyl Phosphate donates carbomyl group to ornithine to form citrulline

Question 18

What combines with citrulline in the urea cycle?

What occurs to this product?

What occurs to this next product?

Answer 18

Citrulline combines with aspartate to form arginosuccinate

Argininosuccinate cleaved to release arginine and create fumarate

Arginine cleaved to yield urea and ornithine

Question 19

What is the main regulatory enzyme of the Urea Cycle?

Answer 19

Carbamoyl Phosphat Synthetase I (CPS I)

Activate: N-Acetylglutamate

Question 20

What are the sources of the Nitrogen (x 2) and Oxygen in Urea?

Answer 20

Nitrogens: Ammonia, Aspartate

Oxygen: CO₂ , H₂O

Question 21

What can increas the synthesis and activity of the urea cycle enzymes?

Answer 21

High protein diet

starvation

Question 22

What links the Urea Cycle to the CAC?

What can these be converted to?

Answer 22

Aspartate and Fumarate

Fumarate: Converted to Malate

Question 23

What cofactors are required to prepare the carbon skeletons to enter the Citric Acid Cycle?

Answer 23

THF, SAM

Tetrahydrobiopterin

Question 24

What AAs can form pyruvate?

Answer 24

Alanine

Serine

Cysteine

Glycine

Threonine

Tryptophan

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Question 25

Where are BCAAs (Isoleucine, Leucine, Valine) metabolized?

Answer 25

Muscle

Question 26

What are limiting AA during periods of tisue growth?

Answer 26

Histidine Arginine

Question 27

AA Derived from Glutamate

Answer 27

Glutamine Arginine Proline **GLUTE GAP**

Question 28

AA Derived from Serine

Answer 28

Glycine Cysteine Ser Glyde Cyster

Question 29

AA Derived from Aspartate

Answer 29

Methionine, Asparagine, Lysine, Threonine Aspartate MALT

Question 30

AA Derived from Pyruvate

Answer 30

Valine, Alanine, Isoleucine, Leucine Pyruvate VAIL

Question 31

Where are major sites of heme synthesis

Answer 31

Liver (cytochromes) RBCs (Hb)

Question 32

PKU

Answer 32

Defect in Phenylalanine Hydroxylase Inability to convert phenylalanine to tyrosine Screened in babies, special diet

Question 33

Alkaptonuria

Answer 33

Defect in homogentisate 1,2-dioxygenase Conversion of homgentisate to maleylacetoacetate Buildup of homogentisate, **black urine**

Question 34

Alanine is converted to what in the liver?

Answer 34

Pyruvate

Question 35

What are the ketogenic AAs?

Answer 35

Leucine, Lysine

Question 36

What AAs are ketogenic and glucogenic?

Answer 36

PITT Phenylalanine Isoleucine Tryptophan Tyrosine

Question 37

What type of reaction is involved in Histamine synthesis

Answer 37

Decarboxylation

Question 38

What is most likely to result from lead poisoning?

Answer 38

Erythropoeietic protoporphyria

Question 39

What is most abundant AA in body?

Answer 39

Glutamine