ChEBI: Pro-Hyp is a dipeptide composed of L-proline and L-hydroxyproline residues. It is a biomarker for bone collagen degradation. It has a role as a diagnostic agent, a human metabolite and a biomarker. It is functionally related to a L-proline and a trans-4-hydroxy-L-proline. It is a tautomer of a Pro-Hyp zwitterion.