3.4.11.6	aminopeptidase B	periodontal ligament	enzyme probably derived from blood	
3.4.24.B4	matrix metalloproteinase-13	periodontal ligament	-	
3.4.24.7	interstitial collagenase	periodontal ligament	-	
3.4.24.24	gelatinase A	periodontal ligament	-	
3.4.24.35	gelatinase B	periodontal ligament	periapical ligament