substrate at temperatures up to 18 u00b0 c did not achieve degradation of the cross linked collagen product soluble collagen was extracted from 2 year old bovine skin and purified purified reconstituted soluble collagen fibrils were irradiated under the conditions described in example 2 in 0 01 and 0 1 catalyst for 6 16 24 and 48 hours attempts were made to dissolve 0 4 mg samples of the reconstituted soluble collagen fibrils at room temperature after they were cross linked in 0 25 nil of 0 5 m acetic acid as well as in 0 250 ml of 0 1 m tris borate buffer pit 8 6 containing 4 m urea and 0 2 sds the control non cross linked fibrils dissolved readily at 0 u00b0 c and rapidly at room temperature in the latter two solutions the collagen suspensions failed to dissolve when heated to 65 u00b0 c some of these suspensions were subjected to page analyses the reconstituted soluble collagen non cross linked fibrils that dissolved showed normal electrophoretic patterns however when the supernatents of the heated cross linked fibrils were run on the gel the electrophoretic patterns were extremely light and barely visible pepsin and collagenase treatments were used to assess the efficiency of the cross linking reaction there was apparently very little if any dissolution caused by the pepsin digestion there was some precipitate left after collagenase treatment aliquots of the supernatents and residues from.