Q.18.57 - An Introduction to General, Organic, and Biological Chemistry

Question

Caprylic acid ${\mathrm{CH}}_3-{\left({\mathrm{CH}}_2\right)}_6-\mathrm{COOH}$ is a C₈  fatty acid found in milk.

a. State the number of $\mathrm{\beta }$-oxidation cycles for the complete oxidation of caprylic acid.

b.  State the number of acetyl CoA from the complete oxidation of caprylic acid.

c. How many ATP are generated from the oxidation of caprylic acid.

Step-by-Step Solution

Answer

a. Caprylic acid, a C₈ monosaturated fatty acid, must go through three cycles of $\beta$-oxidation cycles.

b.  Four acetyl-CoA are produced after eight $\mathrm{\beta }$-oxidation cycles.

c. 50 ATP are generated from the oxidation of caprylic acid.

Step 1: Part (a) Given information

To determine the number of $\mathrm{\beta }$-oxidation cycles.

Step 2: Part (a) Explanation

Acetyl COA is formed when fatty acids are oxidized. Beta oxidation of fatty acids removes two carbons from the carboxylic end in stage two of fat metabolism. Each $\mathrm{\beta }$-oxidation produces acetyl-CoA and a two-carbon shorter fatty acid. $\mathrm{\beta }$-oxidation continues until acetyl-CoA is formed from the fatty acid.

To be entirely oxidized, caprylic acid, a ${\mathrm{C}}_8$ monosaturated fatty acid, must go through three cycles of $\mathrm{\beta }$-oxidation cycles.

Step 1: Part (b) Given information

To find the no. of acetyl CoA produced.

Step 2: Part (b) Explanation

Acetyl COA is formed when fatty acids are oxidized. $\mathrm{\beta }$ -oxidation of fatty acids removes two carbons from the carboxylic end in stage two of fat metabolism. Each $\mathrm{\beta }$-oxidation produces acetyl-CoA and a two-carbon shorter fatty acid. $\mathrm{\beta }$-oxidation continues until acetyl-CoA is formed from the fatty acid.

To be entirely oxidized, caprylic acid, a ${\mathrm{C}}_8$ monosaturated fatty acid, must go through three $\mathrm{\beta }$-oxidation cycles. As a result, four acetyl-CoA are produced after eight $\mathrm{\beta }$-oxidation cycles.

Step 1: Part (c) Given information

To find the ATP generated from the oxidation of caprylic acid.

Step 2: Part (c) Explanation

One NADH, one FADH₂ , and one acetyl-CoA are created in each $\mathrm{\beta }$-oxidation cycle. It's worth noting that NADH and FADH₂  both produce three and two ATP, respectively. Furthermore, the activation of the fatty acid necessitates the use of two ATP molecules.

Caprylic acid goes through three $\mathrm{\beta }$-oxidation cycles, yielding four acetyl-CoA.

Therefore, 50 ATP are generated.