Vitamin C is essential for the hydroxylation of which amino acids during collagen formation?

Vitamin C, also known as ascorbic acid, plays a crucial role in the post-translational modification of collagen. Specifically, it is essential for the hydroxylation of proline and lysine residues within collagen fibers. This hydroxylation process is vital for stabilizing the collagen triple helix structure, which ultimately contributes to the strength and integrity of connective tissues.

During collagen synthesis, proline and lysine undergo hydroxylation to form hydroxyproline and hydroxylysine respectively. This modification increases the stability of the collagen molecule by allowing for additional hydrogen bonding between collagen chains. If there is a deficiency in vitamin C, collagen formation is impaired, leading to weakened connective tissues, a condition commonly associated with scurvy.

The other amino acids listed do not participate in the same hydroxylation reactions required for collagen formation. Methionine and cysteine are involved in other biochemical processes, but they do not undergo hydroxylation in relation to collagen. Similarly, serine and aspartate, along with glutamine and valine, do not have roles in collagen hydroxylation. Understanding these biochemical pathways is essential for grasping the significance of vitamin C in human health and pathophysiology.