Beta Oxidation

Question 1

What is a synthetase vs a synthase?

Answer 1

synthetase: an enzyme that combines two small molecules to form a larger molecule with the help of ATP
synthase: same as synthase but without ATP

Question 2

How is a fatty acid activated for beta oxidation?

Answer 2

1) Nucleophilic oxygen atom of the fatty acid attacks the ⍺-phosphate of ATP forming 2Pi and an acyl adenylate
2) The thiolate anion form of coenzyme A, nucleophile, reacts with the acyl adenylate. AMP is the leaving group and the fatty acyl-CoA thioester is formed

Question 3

Where does beta oxidation occur?

Answer 3

mitochondrial matrix

Question 4

How are fatty acids transported into the mitochondrial matrix?

Answer 4

The fatty acyl CoA becomes carnitine ester and the acyl-carnitine transport moves the ester into the matrix where it can later be converted back to fatty acyl CoA molecule

Question 5

What occurs during the first step of beta oxidation?

Answer 5

FAD forms a double bond between the ⍺ and β carbons of fatty acyl CoA, to turn palmitoyl-CoA into trans - Δ2- Enoyl-CoA.
Coenzyme: acyl-CoA dehydrogenase
Cofactor: FAD

Question 6

What occurs during the second step of beta oxidation?

Answer 6

Water is added to the double bond and trans - Δ2- Enoyl-CoA becomes L-β-hydroxy-acyl-CoA
Coenzyme: Enoyl-CoA hydratase
Cofactor: H2O

Question 7

What occurs during the third step of beta oxidation?

Answer 7

Oxidation of the alcohol by NAD+, L-β-hydroxy-acyl-CoA becomes β-ketoacyl CoA
NAD+: cofactor
β-hydroxyacyl CoA dehydrogenase

Question 8

What occurs during the fourth step of beta oxidation?

Answer 8

Lysis of bond between ⍺ and β carbons of β-ketoacyl CoA
Thiolate anion (CoAS) breaks the ⍺ and β carbon bond of β-ketoacyl CoA to produce Acetyl CoA and Fatty acyl CoA
thiolase: coenzyme
H+: cofactor

Question 9

Who discovered beta oxidation in the it occurs 2 carbons at a time?

Answer 9

Knoop