Figure 1.

Collagen Crosslink Analysis

Patterns of collagen-derived pyridinium crosslinks in unhydrolyzed urine from (A) proband and (B) age-matched healthy control, analyzed as described previously.²⁶ Hydroxylysine glycosides were analyzed by LC/MS/MS with multiple reaction monitoring²⁷ with a ABI QTRAP 3200 instrument. After prefractionation of urines by partition chromatography on cellulose columns, the crosslink components were separated by RP-HPLC and quantified by their natural fluorescence (ex. 295: emm 400 nm) in relation to an internal standard (IS), O-acetyl-pyridinoline (DPD, deoxypyridinoline). Note the absence of Glc-Gal-PYD in (A): When present, Gal-PYD elutes as a partially resolved peak 0.5 min later than Glc-Gal-PYD.