Chapter 24, Problem 24.37AP

Interpretation Introduction

Interpretation:

The initial chemical transformation takes place on a fatty acid to activate it for catabolism should be determined.

Concept introduction:

Fatty acids are aliphatic mono-carboxylic acids that are mostly obtained from the hydrolysis of natural fats and oils. They have a general formula $R-{\left(C{H}_2\right)}_n-COOH$, n is mostly an even number of carbon atoms (4 to 20) with a few exceptions that have an odd number

Fatty acids in the body are mostly oxidized by $\text{β}$ oxidation.

$\text{β-oxidation}$ is the oxidation and splitting of two carbon units at $\text{β}$- carbon atom. This results in sequential removal of 2 carbon fragments as acetyl CoA until the complete oxidation of fatty acids.

The four important steps of $\text{β-oxidation}$ are,

Step 1: Dehydrogenation of the fatty acyl-CoA to make ‘trans’ double bond between $\text{α}$ and $\text{β}$ carbon.

• Short, medium and long chain acyl-CoAdehydrogenases
• Electron removed transferred to FAD

Step 2: Hydration of the double bond.

Step 3: Dehydrogenation of the $\text{β-hydroxyl}$ group to a ketone.

• Electron removed transferred to $NA{D}^{+}$

Step 4: Acylation-addition of CoA and production of and production of acetyl-CoA

Oxidation: Losing electrons, increasing oxidation number, addition of oxygen and removal of hydrogen.

Reduction: Gaining electron, decreasing oxidation number, addition of hydrogen and removal of oxygen.