Chapter 24, Problem 24.11UKC

Oxygen is not a reactant in the β oxidation of fatty acids. Can β oxidation occur under anaerobic conditions? Explain.

Interpretation Introduction

Interpretation:

Whether $\beta oxidation$ occur under anaerobic conditions or not has to be explained.

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.

$\text{β-oxidation}$ 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.

Electron transport chain is the final common pathway in aerobic cells by which electrons and hydrogen (NADH and FADH2) derived from foodstuffs are transferred to oxygen to form water and finally produce ATP (energy).

Answer to Problem 24.11UKC

Oxygen is needed to reoxidize reduced coenzymes, formed in $\text{β-oxidation}$, that enter the electron transportation. Therefore, $\text{β-oxidation}$ cannot occur under anaerobic condition.

Explanation of Solution

Main points related to $\beta oxidation$ can be listed as follows,

$\begin{array}{cc}& \beta oxidation\\ \text{Site}& \text{Mitochodrial}\text{matrix}\\ \text{Activated}\text{by}& \begin{array}{l}\text{Glucagon}\\ \text{Low}\text{blood}\text{glucose}\end{array}\\ \text{Initial}\text{substrate}& \text{Fatty}\text{acid}\\ \text{Coenzymes}& \text{FAD,}{\text{NAD}}^{\text{+}}\\ \text{Function}& \text{Cleaves}\text{two}\text{carbon}\text{acyl}\text{group}\\ \text{Final}\text{product}& \text{Acetyl}\text{CoA}\text{units}\end{array}$

Since oxygen is not a reactant in $\beta oxidation$ of fatty acids but it is needed to reoxidize reduced coenzymes, formed in $\text{β-oxidation}$, that enter the electron transportation.

Therefore, $\text{β-oxidation}$ cannot occur under anaerobic condition.

Conclusion

$\text{β-oxidation}$ cannot occur under anaerobic condition.