Table 1. Chondroitin sulfate disaccharide analysis in newly synthesized proteoglycans from cartilage organ cultures.

Cartilage slices from wild-type and dtd mice were metabolically labelled with [³⁵S]cysteine and [³H]glucosamine; GAGs were then purified and digested with chondroitinase ABC and ACII and released disaccharides were separated by HPLC and counted for ³H activity. The relative amount of non-sulfated disaccharide (ΔDi-0S) in dtd mice was significantly increased compared with wild-type mice, indicating proteoglycan undersulfation. At the same time, the ³⁵S/³H ratio in mono-sulfated disaccharides was measured and values demonstrated that sulfur from cysteine catabolism can provide sulfate for proteoglycan sulfation as observed in GAGs. Results shown are the means±S.D. for cartilage organ cultures from four dtd and wild-type mice. *P<0.05; **P<0.001.

	Disaccharide (%)*			35S/3H**
	ΔDi-0S	ΔDi-4S	ΔDi-6S	ΔDi-4S	ΔDi-6S
dtd	42.25±4.58	55.75±4.30	1.99±0.34	0.614±0.046	0.841±0.056
Wild-type	11.22±0.48	86.10±0.68	2.68±0.27	0.110±0.015	0.124±0.025