Age-related changes of the dermatan sulfate containing small proteoglycans in bovine tendon

Sulfated proteoglycans of fetal, newborn and adult bovine tendon are extracted with neutral salt and then with 4 M guanidine HCl in the presence of proteinase inhibitors. Dermatan sulfate containing small proteoglycans are separated from chondroitin sulfate rich proteoglycans by CsCl-gradient centrifugation, by affinity chromatography using concanavalin A and by molecular sieve chromatography. These proteoglycans are comprised of a core protein with an average Mr of about 53,000 on polyacrylamide gel electrophoresis with SDS and of dermatan sulfate side chains with Mr 25,000-38,000 by gel chromatography. The tryptic peptides patterns observed in the small proteoglycans from newborn calf and adult bovine tendon are identical but are distinct from those of embryonic calf tendon. The patterns of the tryptic peptides of the core proteins from embryonic calf tendon are similar to those from the dermatan sulfate proteoglycans of calf skin. These results indicated that genetically independent genes of the core proteins from dermatan sulfate proteoglycans in tendon tissues were expressed by aging.