Fluorophore-assisted carbohydrate electrophoresis (FACE) analysis. (a) Representative FACE gel of hyaluronidase and chondroitinase digestion products from a 30-year-old cadaveric control. Lanes A and B contain a mixture of predefined fluorotagged saccharide standards. Lane A: (1) ΔDiHA, (2) ΔDi6S, (3) ΔDi4S, (4) ΔDi2S, (5) ΔDi4,6S, (6) ΔDi2,6S, (7) ΔDi2,4S, (8) ΔTri2,4,6S. Lane B: (9) N-acetylgalactosamine (GalNAc), (10) ΔDi0S, (11) GalNAc6S, (12) GalNAc4S, (13) 4-/6-sulphated GalNAc. Samples were digested with hyaluronidase (from Streptococcus dysgalactiae) (lane C) and chondroitinase ABC (lane D). (b) Representative FACE gel of chondroitin sulphate termini products from a 22-year-old cadaveric control (lane B) and a 22-year-old autologous chondrocyte implantation (ACI) patient (lane C). Lane A contains a mixture of predefined fluorotagged saccharide standards. Lane A: (1) GalNAc, (2) GalNAc6S, (3) GalNAc4S, (4) GalNAc4,6S, (5) GalNAc2,4,6S. (c) Representative FACE gel of keratanase II and endo-β-galactosidase digestion products obtained from full-depth cartilage of a 30-year-old cadaveric control (lanes E and F) and a 27-year-old ACI patient (lanes G and H). Lanes A to D contain a mixture of predefined fluorotagged saccharide standards. Lanes A to D: (1) Galβ1,2 [fucα1,3]GlcNAc6S, (2) Galβ1,4GlcNAc6S, (3) Gal6Sβ1,4glcNAc6S, (4) NeuAα2,3Gal6Sβ1,4GlcNAc6S, (5) GlcNAcβ1,3Gal, (6) GlcNAc6Sβ1,3Gal. ΔDi0S, unsulphated chondroitin sulphate disaccharide; ΔDi4S, chondroitin-4 sulphate disaccharide; ΔDi6S, chondroitin-6 sulphate disaccharide; ΔDiHA, hyaluronan disaccharide.