KIN 343 - 11.8 Vit B2 Functions

Riboflavin, also known as vitamin B2, is essential for multiple biological functions.
Its derivatives, flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN), play crucial roles as electron carriers in metabolic pathways.

FAD and FMN function as coenzymes involved in redox (oxidation-reduction) reactions.
Major role in enzymatic reactions by facilitating the transfer of electrons.

Oxidation of Pyruvate to Acetyl CoA
- Riboflavin is integral for converting pyruvate into Acetyl CoA, which is vital for entry into the TCA (Krebs) cycle.
- FAD accepts electrons from pyruvate and is reduced to FADH2.
- FADH2 then donates electrons to NAD+, generating NADH while regenerating FAD.
- This process enables glucose to be utilized as an energy source.
Beta Oxidation of Fatty Acids
- FAD acts as an oxidizing agent during the beta oxidation of fatty acids, essential for lipid metabolism.
- Each cleavage of a carbon atom results in FAD accepting electrons, transforming into FADH2, which is crucial for the breakdown of fats.
- The energy derived from fatty acids is due to the ability of FADH2 to transfer electrons into the electron transport chain, facilitating ATP production.
Role in the TCA Cycle
- FAD is necessary for the TCA cycle and electrons are transferred from the cycle to the electron transport chain.
- Specifically involved in the conversion of succinate to fumarate, generating FADH2.
- Facilitates the transfer of electrons, leading to ATP synthesis during cellular respiration.

Riboflavin is crucial for:
- The conversion of carbohydrates and fats into usable energy in the form of ATP.
- Direct involvement in the metabolic pathways necessary for energy production.
Without riboflavin, the body cannot efficiently metabolize carbohydrates or fats, underscoring its importance in energy metabolism.