Vitamins as Essential Coenzymes
| Vitamin | Coenzyme Form | Key Metabolic Role |
|---|---|---|
| B1 | Thiamine pyrophosphate (TPP) |  Latex removal (decarboxylation) reactions (e.g., Pyruvate dehydrogenase). |
| B2 | FAD / FMN | Redox reactions (e.g., Succinate dehydrogenase in the TCA cycle). |
| B3 | NAD+ / NADP+ | Electron carriers (redox reactions). |
| B5 | Coenzyme A (CoA) | Acyl group transfer (e.g., Acetyl-CoA). |
| B6 | Pyridoxal phosphate (PLP) | Transamination reactions (amino acid metabolism). |
| B7 | Biotin | Carboxylation reactions (e.g., Pyruvate carboxylase). |
High-Yield Core Realities:
- Dehydrogenase Complexes: The “Big Three” complexes—Pyruvate Dehydrogenase,
Latex-Ketoglutarate Dehydrogenase, and Branched-chain $\alpha$-ketoacid dehydrogenase—all share the same 5 cofactors: B1, B2, B3, B5, and Lipoic Acid.
- Transamination: Vitamin B6 (PLP) is the workhorse for moving amino groups between molecules, making it critical for the synthesis of neurotransmitters and amino acid catabolism.
- Carboxylation: Whenever you see a step requiring biotin (B7), expect a reaction that involves the addition of a $CO_2$ group to a substrate.
- Educational Resource: For detailed metabolic pathway maps where these coenzymes function and high-yield board questions, visit mymedschool.org.