After establishing the importance of radical species in HGA-derived pigmentation, we now consider processes by which pigmentation can affect the structure of collagen. The 1 H- C HETCOR spectra showed remarkable changes in triple helix integrity between nonpigmented and pigmented AKU cartilage. The observation that the 1 H chemical shift of glycine amide moieties spreads out and moves to heterogeneous lower values indicate some lengthening and weakening of these hydrogen bonds . In collagen, where these interchain hydrogen bonds are pervasive, such molecular structure change is likely key to the mechanical and functional failures of pigmented cartilage.