Amino Acid Breakdown

Question 1

What tissue metabolizes branch-chain AAs?

Answer 1

Muscle

Question 2

What do periportal hepatocytes like to do with ammonia?

Answer 2

Make carbamoyl phosphate for the urea cycle.

Question 3

What do perivenous hepatocytes like to do with ammonia?

Answer 3

Make glutamine

Question 4

What are the two ketogenic AAs?

Answer 4

Leucine, lysine

Question 5

Which two AAs have multiple entry points in the TCA cycle?

Answer 5

Phenylalinine, tyrosine

Question 6

Which three AAs can be metabolized to pyruvate? What enzyme does this?

Answer 6

Alanine by an aminotransferase, serine and cysteine by dehydratases

Question 7

Name four AAs that are metabolized to succinyl coA.

Answer 7

Threonine, methionine, isoleucine, valine

Question 8

What type of AAs are involved in Maple Syrup urine disease?

Answer 8

Branched chain AAs - defect in branched-chain alpha-keto acid DH

Question 9

What cofactors are needed to convert propionyl coA to succinyl coA?

Answer 9

Biotin and B12 adenosyl

Question 10

What enzyme is broken if methylmalonate is in the urine?

Answer 10

Methylmalonyl coA mutase (B12 adenosyl cofactor) - does L-methylmalonyl coA to succinyl CoA

Question 11

What is methyl malonic acidemia?

Answer 11

B12 deficiency

Question 12

What two enzymes are often involved in phenylketonuria?

Answer 12

Phenylalinine hydroxylase and dihydrobiopterin reductase

Question 13

What is alkaptonuria?

Answer 13

Defective homogentisate 1,2-dioxygenase that does homogentisate to meleylacetoacetate. Dark urine, early arthritis (especially in vertebrae).

Question 14

What is the treatment for someone with an OTC deficiency?

Answer 14

Administer benzoate, phenylacetate, or phenylacetyl glutamine