NCIt definition : A nonessential amino acid derivative formed during post-translational protein modification
through hydroxylation of the amino acid proline by the enzyme prolyl hydroxylase which
requires vitamin C as a co-factor. Hydroxyproline is a major component of the protein
collagen and plays a key role in the stability of the collagen triple helix. It can
be used as an indicator to determine the amount of collagen. Increased hydroxyproline
levels in the urine and/or serum are normally associated with degradation of connective
tissue. Vitamin C deficiency decreases the conversion of proline to hydroxyproline,
which leads to reduced collagen stability.;