Table 1.

MMP classification and substrate specificity^15,21–24

Class name	MMPs	ECM substrates	Non-ECM substrates [among others]
			Substrate	Result
Collagenases	MMP-1, -8, and -13	Collagen types I, II, III, and V triple-helices	α1-antitrypsin Plasminogen activator inhibitor-2 α2-antiplasmin Latent TGF-β1	Inactive SERPINA1 Inactive PAI2 [SERPINB2] Inactive SERPINF2 Activated TGF-β1
Gelatinases	MMP-2 and -9	Gelatin, denatured collagens, collagen type IV	Latent TGF-β1 α1-antitrypsin Plasminogen	Activated TGF-β1 Inactive SERPINA1
Stromelysins	MMP-3, -10, and -11	ECM substrates [except triple-helical collagens]	α1-antitrypsin Plasminogen activator inhibitor-2 Endostatin Latent TGF-β1 Collagenases	Inactive SERPINA1 Inactive PAI2 Activation Activated TGF-β1 Activation
Matrilysins	MMP-7 and -26	ECM substrates [except triple-helical collagens]	α1-antitrypsin	Inactive SERPINA1
Macrophage elastase	MMP-12	Elastin	α1-antitrypsin
Others	MMP-19, -20 -21, -23A/B, -27, and -28
Membrane-type MMPs	MMP-14, -15, -16, -17, -24, and -25