Collagenase-released non-collagenous proteins of cortical bone matrix

Two distinct groups of non-collagenous components were isolated from rat cortical bone gelatin which had previously been digested with purified bacterial collagenase. One component was disulfide-bonded, strongly acidic, trypsin-labile glycoprotein aggregate with a molecular mass of more than 100,000 daltons. When reduced with beta-mercaptoethanol this protein disaggregated into subunits with a molecular mass of about 60,000 daltons. The other components consisted of a group of polypeptides with a molecular mass of about 5,000 daltons. The latter group was present in collagenase digests prepared from normal bone gelatin but was hardly detectable or absent in digests of gelatin prepared from either autolyzed, trypsinized or lathyritic bone, or from the residue of neutral salt extracted rat tail tendon.