2: Fatty Acid Oxidation

Question 1

Two phases of FA oxidation

Answer 1

1. FA activation + transport into mito

2. Beta-oxidation

Question 2

Where do the two phases of FA oxidation occur?

Answer 2

1: cytosol
2: mito matrix

Question 3

SCFAs, MCFAs, LCFAs, and VLCFAs: pathway into the mito

Answer 3

SCFAs + MCFAs: diffuse freely into mito
LCFAs: use carnitine shuttle
VLCFAs: oxidation in peroxisomes THEN use carnitine shuttle

Question 4

What is considered a VLCFA?

Answer 4

> 20C

Question 5

What is formed by B-oxidation of VLCFAs in peroxisomes?

Answer 5

H2O2, no ATP

Question 6

Four steps of B-oxidation

Answer 6

1. Oxidation
2. Hydration
3. Oxidation
4. Thiolysis

Question 7

What enzyme does the oxidation in B-oxidation?

Answer 7

Acyl CoA dehydrogenase (ACAD)

Question 8

Types of ACAD

Answer 8

For short chain, medium, long, and V long chain FAs

Question 9

Which type of ACAD is most common for inherited defects?

Answer 9

MCAD

Question 10

Three things generated by B-oxidation?

Answer 10

Acetyl coA, FADH2, NADH

Question 11

Three steps in breaking down unsaturated FAs

Answer 11

1. Metabolize until unsaturations occurs
2. Reductase: reduces double bond
3. Isomerase: removes disruptive double bond

Question 12

Two most notable defective enzymes in FA Oxidation

Answer 12

Carnitine shuttle, acyl CoA dehydrogenase

Question 13

MCAD deficiency

Answer 13

Impaired breakdown of MCFAs -> secondary carnitine deficiency

Question 14

Treatment of MCAD

Answer 14

Patient just needs to depend on glucose as energy source -> excellent prognosis if caught early enough

Question 15

What are LCFAs linked to while in the blood before breakdown?

Answer 15

Albumin