Amino Acid Metabolism

Question 1

Extracellular Proteolytic Enzymes Control

Answer 1

Secreted as inactive zymogens; activated by proteolytic cleavage: Trypsin activates chymotrypsinogen.

Question 2

Essential Amino Acids

Answer 2

Phenylalanine
Valine
Thryptophan
Threonine 
Isoleucine
Methionine
Histidine
Arginine
Leucine
Lysine
Glutamine

Question 3

What are the Ketogenic Amino Acids?

What are they metabolized into?

Answer 3

Leucine and Lysine. They are metabolized into Acetyl CoA and acetoacetate.

Question 4

What are the glycogenic Amino Acids?

To what cycle do they contribute?

Answer 4

most of them. They participate in the TCA Cycle intermediates.

Question 5

What are the Amino Acids metabolized and added to alpha-Ketoglutarate of TCA?

Answer 5

"PHAG"
Proline
Histidine
Arg
Gln
These 4 are converted to Glu which enters the TCA cycle.

Question 6

Succinyl CoA Amino Acids add ons.

Which of these are branched?

Answer 6

"I think My Vagina Succs"
Thr
Met
Ile
Val
All of them convert to Propionyl CoA, which converts to Methylmalonyl CoA, which converts to Succinyl CoA.

Ile and Val are branched.

Question 7

Acetyl CoA Amino Acid Add on

Answer 7

Leucine. Barched AA, causes Maple syrup Urine Disease.

Question 8

What AA is metabolized and introduced to Fumarate in TCA?

Answer 8

Phenylalanine is converted to Tyrosine by Phenylalanine Hydroxylase. Tyrosine is converted into Fumarate down the line.

Question 9

Phenylalanine Hydroxylase function

Answer 9

Converts Phenylalanine to Tyrosine.

Question 10

What AA is metabolized to Oxaloacetate?

Answer 10

Asn to Asp to Oxaloacetate

“OX with a big AAsp”

Question 11

What is Phenylketonuria and what causes it?

Answer 11

Is caused by defects in the Phenylalanine Hydroxylase. Instead of being converted to Tyrosine, it is converted to Phenylpyruvate and then to Phenyllactate and Phenylacetate.

Question 12

What are the Tryptophan derivatives?

Answer 12

Trp is converted to 5hydroxytrp, which is decarboxylated to Serotonin- can convert to Melatonin.

Question 13

What are Tyrosine derivatives?

Answer 13

Tyrosine is converted to Dopamine, which can be further converted to Norepinephrine and Epinephrine.
Can also be converted into T3 and T4
Can also be converted to Melanin.

Question 14

What causes Albinism?

Answer 14

Conversion of Tyrosine to Melanin is blocked due to defects in enzyme Tyrosinase.

Question 15

How is Ammonia toxicity caused?

Answer 15

Caused by excessive Ammonia due to disorders in the Urea Cycle (Ornithine cycle).

Question 16

What Amino Acid makes Ornithine?

Answer 16

Arginine.

Question 17

What Amino Acids make up Creatine?

Answer 17

Met, Arg, Gly

Question 18

What kind of proteins are degraded during proteasomal degradation?

Answer 18

Polyubiquinated proteins. This is a selective process.

Question 19

What are the 2 anaplerotic reactions of TCA cycle?

Answer 19

1. Degradation of amino acids

2. Decarboxylation of Pyruvate.

Question 20

What causes Homocystinuria?

Answer 20

Deficiency in vitamins: B6, 12, or Biotin. Also genetic defects in enzyme: Cystathionine-beta-synthase. This causes defective metabolism of homocysteine.

Question 21

Function of enzyme Cystathionine-beta-synthase?

Answer 21

Converts Homocysteine to cystathionine during the Met metabolism.

Question 22

What are the branched chain amino acids?

Answer 22

LIV: Leucine, Isoleucine, Valine.

Question 23

Maple Syrup Urine Disease

Answer 23

Rare autosomal disease resulting from deficiency in the Branched -chain alpha Keto acid dehydrogenase complex(BCKD) activity which results in branched-chain Ketoaciduria.

Question 24

What enzyme is the Rate Limiting step of Ornithine?

Answer 24

Carbamoyl Phosphate Synthetase. NAG is an activator.

Question 25

What are Transaminases/Aminotransaminases?

What co-enzyme is required?

Answer 25

They transfer an amino group to a alpha ketoacid.

PLP(derivative of B6)

Question 26

Ammonia is removed as Glu and Gln in the_______

Answer 26

Brain

Question 27

Ammonia is removed as Gln and Ala in the________

Answer 27

Tissues