Summary

Vitamin C (Ascorbic Acid) is a water-soluble vitamin important as a cofactor for hydroxylase enzymes. It is a cofactor for dopamine beta-hydroxylase, facilitating the conversion of dopamine to norepinephrine. Vitamin C is also involved in collagen synthesis, as a cofactor for hydroxylation of proline and lysine residues. As an antioxidant, Vitamin C also plays an important role in the reduction of iron (III) to iron (II), which is required for enteric absorption of iron. This property also makes vitamin C useful as an ancillary treatment for methemoglobinemia.

Key Points

• Ascorbic Acid (Vitamin C)
  • Water-soluble antioxidant found in fruits and vegetables
  • Reduces iron: Fe3+ to Fe2+
    • Facilitates iron absorption at GI tract
    • Mechanism of treatment for methemoglobinemia
  • Key roles in hydroxylase enzymes
    • Hydroxylation of proline and lysine residues (in Collagen Synthesis)
      • prolyl and lysyl hydroxylases
    • dopamine B–hydroxylase, converts dopamine to norepinephrine (in Catecholamine Synthesis)

Find Vitamin C Biochemistry and other Vitamins among Pixorize's visual mnemonics for the USMLE Step 1 and NBME shelf exams.