Determination of 4-hydroxyproline
was performed according to the procedure suggested by Kindt et al.
A simple method to determine nanogram levels of 4-hydroxyproline
in biological tissues.
Collagen chains that do not contain 4-hydroxyproline
cannot fold into triple helical molecules that are stable at body temperature (Pihlajaniemi et al.
13,14) Collagen contains 12% of the aminoacid proline and 9% of 4-hydroxyproline
Collagen hydrolysate provides the specific amino acids -- glycine, proline and 4-hydroxyproline
-- needed for joint cartilage synthesis.
Prolyl 4-hydroxylase catalyzes the hydroxylation of proline residues in repeating X-Pro-Gly triplets, thus forming the 4-hydroxyproline
required for the correct folding of newly synthesized collagen (Kivirikko and Myllyharju, 1998; Kivirikko and Pihlajaniemi, 1998; Myllyharju, 2003).
Its primary sequence exhibits tandem repeats of the decapeptide motif Ala-Lys-Pro-Ser-Tyr-diHyp-Hyp-Thr-DOPA-Lys, where diHyp and Hyp are 3,4-dihydroxyproline and 4-hydroxyproline
, respectively (Waite et al.