Vitamin B1 (Thiamine) Biochemistry



Thiamine (Vitamin B1) is a water-soluble vitamin and an important constituent of TPP (thiamine pyrophosphate), a cofactor found in several important dehydrogenase reactions. Specifically, TPP is an important cofactor for pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, and branched-chain ketoacid dehydrogenase. Besides dehydrogenase reactions, TPP also serves an important role as a cofactor for transketolase.

Key Points

  • Vitamin B1 (Thiamine)
    • Active form is thiamine pyrophosphate (TPP), a cofactor for several dehydrogenases and other enzymes:
      • Pyruvate dehydrogenase
        • Links glycolysis to TCA cycle (see Pyruvate Metabolism), enabling cells to metabolize glucose to produce energy
        • Deficiency leads to necrosis of some glucose-dependent tissues (esp. mamillary body in brain), such as seen in Thiamine Deficiency
      • α-ketoglutarate dehydrogenase
        • Enzyme in the TCA cycle
      • Transketolase
      • Branched-chain ketoacid dehydrogenase

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