Fate of Carbon Skeleton in Amino Acid - Catabolism of BAA

Question 1

Catabolism of branched chain amino acids involves these 3 amino acids

Answer 1

Leucine
Isoleucine
Valine

Question 2

Branched chain amino acids are not made by humans hence

Answer 2

essential

Question 3

Where is catabolism of BAA initiated, what does it yield and what is the yield used for?

Answer 3

Initiated in the muscles
Yields NADH and FADH2
Yield is used for ATP generation

Question 4

Products of catabolism of leucine are

Answer 4

Acetyl CoA and Acetoacetyl COA(Acetoacetate)

Question 5

Products of valine catabolism

Answer 5

Propionyl CoA and Carbon dioxide

Question 6

Products of isoleucine catabolism

Answer 6

Propionyl CoA and Acetyl CoA

Question 7

Leucine is …….

Answer 7

ketogenic

Question 8

Valine is …..

Answer 8

glucogenic

Question 9

Isoleucine is ………..

Answer 9

both ketogenic and glucogenic

Question 10

The glucogenic precursor of succinyl CoA is

Answer 10

propionyl CoA

Question 11

What makes amino acid oxidation different from fatty acid oxidation?

Answer 11

debranching reaction for each intermediate.

Question 12

What step commences catabolism of branched chain amino acids?

Answer 12

conversion of amino acid to an α-keto acid by an amino transferase

Question 13

Apart from the muscle, BAA catabolism is also demonstrated in

Answer 13

adipose tissues, brain tissues and kidneys

Question 14

After an α-keto acid has been produced, what’s the next step?

Answer 14

an enzyme complex, α-keto acid dehydrogenase complex will act on it

Question 15

How is the α-keto acid dehydrogenase complex modified?

Answer 15

by covalent modification

Question 16

How is α-keto acid dehydrogenase complex activated or inactivated?

Answer 16

activated by dephosphorylation

inactivated by phosphorylation

Question 17

What disease is associated with the deficiency or absence of α-keto acid dehydrogenase complex?

Answer 17

Maple Syrup Urine Disease (MSUD)

Question 18

What is MSUD characterized by?

Answer 18

the accumulation of α-keto acids in the blood and their excretion in urine

Question 19

What signs can help identify someone with MSUD?

Answer 19

the sweat or urine of the affected individual has the odor of maple syrup or burnt sugar

Question 20

An associated condition to MSUD

Answer 20

abnormal development of brain, leading to mental retardation or death in infancy

Question 21

How can MSUD be managed?

Answer 21

restricting the intake of BAA

some cases respond to the intake of large doses of thiamine

Question 22

A variant of MSUD is

Answer 22

Intermittent Branched Chain Ketonuria

Question 23

Intermittent Branched Chain Ketonuria is characterized by

Answer 23

less severe deficiency of the α-keto acid dehydrogenase complex

Question 24

What makes Intermittent Branched Chain Ketonuria different from MSUD?

Answer 24

symptoms appear later in life and occurs only intermittently

Question 25

How is Intermittent Branched Chain Ketonuria managed?

Answer 25

Restriction of the intake of BAA is more effective

Question 26

What is Isovaleryl Acidaemia?

Answer 26

Disease cause by the deficiency of Isovaleryl CoA dehydrogenase required in Leucine catabolism

Question 27

What is a sign in someone with Isovaleryl Acidaemia?

Answer 27

breath and urine of affected individual has cheesy odor

Question 27

What is a sign in someone with Isovaleryl Acidaemia?

Answer 27

breath and urine of affected individual has cheesy odor

Question 28

What happens when a person with Isovaleryl Acidaemia is fed with protein?

Answer 28

may present with vomiting, acidosis and coma

Question 29

Affected subjects of Isovaleryl Acidaemia may present with

Answer 29

mental retardation

Question 30

How can Isovaleryl Acidaemia be managed?

Answer 30

restriction in the intake of leucine