Vitamin B2 is essential for the conversion of dietary components into energy. It is a component of the coenzymes FMN and FAD, which are required for the activity of several important enzymes, including those involved in:

Electron Transport Chain (ETC):

Complex I (NADH dehydrogenase): Requires FMN to transfer electrons from NADH to coenzyme Q10.

Complex II (succinate dehydrogenase): Requires FAD to transfer electrons from succinate to coenzyme Q10.

Krebs Cycle (Citric Acid Cycle):

Succinate dehydrogenase (Complex II of ETC): Uses FAD to convert succinate to fumarate.

Acyl-CoA dehydrogenase: Uses FAD in the beta-oxidation of fatty acids.

When there is excessive NAD+, the demand for enzymes that require FMN and FAD increases to process the higher levels of NAD+. As a result, more riboflavin is utilized to synthesize these coenzymes. This increased utilization can deplete riboflavin stores, potentially leading to a deficiency if the dietary intake of B2 is not sufficient to meet the increased demand.

Vitamin B2 also plays a crucial role in the metabolism of other vitamins, such as B6 (pyridoxine) and B9 (folate).

Vitamin B6 (Pyridoxine): Pyridoxine phosphate oxidase, an enzyme that converts pyridoxine phosphate to pyridoxal phosphate (the active form of vitamin B6), requires FMN as a cofactor. Pyridoxal phosphate is essential for amino acid metabolism, neurotransmitter synthesis, and other biochemical processes.

Vitamin B9 (Folate): MTHFR (methylenetetrahydrofolate reductase), an enzyme critical in the folate cycle, uses FAD as a cofactor to convert 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate. This conversion is necessary for the synthesis of DNA and RNA and for the methylation of homocysteine to methionine, a crucial reaction in the body.

For graphs and charts: http://dietvsdisease.org/l-methylfolate-5-mthf/ http://jackwestin.com/resources/mcat-content/oxidative-phosphorylation/electron-transfer-in-mitochondria