Question

2,4-Dienoyl-CoA reductase is used in the oxidation of: (A) saturated fatty acids. (B) monounsaturated fatty acids. (C) polyunsaturated fatty acids. (D) cholesterol.

Short answer

Option C: polyunsaturated fatty acids.

Step-by-step solution

- Understand Enzyme Function

Identify the function of 2,4-Dienoyl-CoA reductase. This enzyme is involved in the metabolism of polyunsaturated fatty acids. Specifically, it helps in the reduction of conjugated double bonds in fatty acid chains, which is essential for the proper oxidation of these fatty acids.

- Analyze Each Option

Look at each option to see which one involves polyunsaturated fatty acids: - (A) Saturated fatty acids have no double bonds. - (B) Monounsaturated fatty acids have one double bond. - (C) Polyunsaturated fatty acids have two or more double bonds. - (D) Cholesterol is a sterol and does not have double bonds like polyunsaturated fatty acids.

- Match Enzyme with Correct Fatty Acid

Since 2,4-Dienoyl-CoA reductase is used in the reduction of double bonds, it is specifically involved in the metabolism of polyunsaturated fatty acids (Option C).

Key concepts

Fatty Acid Metabolism

Fatty acid metabolism is a key biological process where fats are broken down to produce energy. This process occurs in the mitochondria, the powerhouse of the cell. Here's a simple breakdown:

• It starts with the breakdown of triglycerides into free fatty acids and glycerol.
• The free fatty acids are transported into the mitochondria.
• Once inside, they undergo β-oxidation, a series of reactions that remove two-carbon units from the fatty acid chain, converting them into Acetyl-CoA.
• The Acetyl-CoA enters the citric acid cycle (Krebs cycle) to produce ATP, the primary energy currency of the cell.

An important aspect of fatty acid metabolism includes the oxidation of different types of fatty acids: saturated, monounsaturated, and polyunsaturated. Each type involves specific enzymes to facilitate their breakdown.

Polyunsaturated Fatty Acids Oxidation

Polyunsaturated fatty acids (PUFAs) are a type of fat found in our diet that have more than one double bond in their chemical structure. These double bonds make PUFAs more complex to oxidize compared to saturated and monounsaturated fatty acids.
During PUFA oxidation:

• Special enzymes are required to manage their multiple double bonds. One such enzyme is 2,4-Dienoyl-CoA reductase.
• 2,4-Dienoyl-CoA reductase specifically acts on the conjugated double bonds found in PUFAs.
• It converts these double bonds into a form that can be further processed in the β-oxidation pathway.

Understanding the oxidation of PUFAs is crucial as they play significant roles in cellular function and overall health, impacting inflammation and cell signaling.

Enzyme Function

Enzymes are biological catalysts that speed up chemical reactions in the body without being consumed in the process. Each enzyme is specific to a particular reaction or type of reaction. Let's discuss the function of the enzyme 2,4-Dienoyl-CoA reductase:

• It is specifically used in the oxidation of polyunsaturated fatty acids (PUFAs).
• The enzyme helps to reduce conjugated double bonds in PUFAs, preparing them for further decomposition through β-oxidation.
• This reduction is critical because without it, the oxidation process would halt, preventing the complete breakdown of PUFAs into usable energy.

This functionality is an excellent example of how enzymes ensure complex biochemical pathways operate efficiently and effectively.