as well as their respective enzymes (HYA, ADA, COL) to obtain fingerprints of their secondary structures (Figure ). The CD spectra of the substrates (HA, ACAN, COL2) displayed distinctive CD features, reflecting their chirality. HA showed a strong negative peak around 210 nm, consistent with the CD of GAGs. ACAN displayed fairly weak CD signatures, yet its negative profile below 200 nm suggests the presence of random coil structures. The CD spectrum of COL2 had the distinctive signature of a polyproline helical fold, as expected for collagen. The CD spectra of HYA and ADA suggested that the two enzymes are predominantly α-helical with negative ellipticities at 208nm and 222 nm, and a positive peak at 193 nm, consistent with published structural data of these two proteins. COL displayed a CD spectrum with negative ellipticity at ~210 nm and weak positive ellipticity below 200 nm. This suggested a significant random coil contribution to an otherwise predominant β-sheet structure since COL has a β-sheet rich fold.