Clostridial collagenases are among the most efficient degraders of eukaryotic collagen known; saprophytes use collagen as a carbon source while pathogens additionally digest collagen to aid in host colonization. Has both tripeptidylcarboxypeptidase on Gly-X-Y and endopeptidase activities; the endopeptidase cuts within the triple helix region of collagen while tripeptidylcarboxypeptidase successively digests the exposed ends, thus clostridial collagenases can digest large sections of collagen (PubMed:3002446). Active on soluble type I collagen, insoluble collagen, azocoll, soluble PZ-peptide (all collagenase substrates) and gelatin (PubMed:9922257). The full-length protein has collagenase activity, while the in vivo derived C-terminally truncated shorter versions only act on gelatin (PubMed:9922257). In vitro digestion of soluble calf skin collagen fibrils requires both ColG and ColH; ColG forms missing the second collagen-binding domain are also synergistic with ColH, although their overall efficiency is decreased (PubMed:18374061, PubMed:22099748). The activator domain (residues 119-388) and catalytic subdomain (389-670) open and close around substrate using a Gly-rich hinge (387-397), allowing digestion when the protein is closed (PubMed:21947205, PubMed:23703618). Binding of collagen requires Ca(2+) and is inhibited by EGTA; the collagen-binding domain (CBD, S3a plus S3b) specifically recognizes the triple-helical conformation made by 3 collagen protein chains in the triple-helical region (PubMed:11121400). Isolated CBD (S3a plus S3b) binds collagen fibrils and sheets of many tissues (PubMed:11913772). Digestion of native collagen in the triple helical region at Xaa-|-Gly bonds. With synthetic peptides, a preference is shown for Gly at P3 and P1', Pro and Ala at P2 and P2', and hydroxyproline, Ala or Arg at P3'. Binds about 7 Ca(2+) per subunit (PubMed:6087888). The metallopeptidase and PKD domains each bind 1 Ca(2+), while each CDB binds 2 (PubMed:12682007, Ref.21, PubMed:23144249, Ref.27). Binds 1 catalytic Zn(2+) per subunit, a Zn-free form has been crystallized (PubMed:21947205). Inhibited by 1-10-phenanthroline (PubMed:18937627). Inhibited by peptidomimetic isoamyl-phosphonyl-Gly-Pro-Ala, which binds to Zn(2+) (PubMed:21947205). Inhibited by broad-spectrum zinc metalloprotease inhibitor batimastat (PubMed:28820255). N-aryl mercaptoacetamide-based inhibitors have been isolated that act on clostridial collagenases with submicromolar affinity while having negligibile activity on human collagenases (PubMed:28820255). kcat is 0.11/sec, using a catalytic fragment (119-790) on an artificial substrate. RNA levels are high in late logarithmic phase. The mature protein has 4 domains; a metalloprotease domain (S1, approximately residues 111-786), S2 (877-882, equivalent to PKD), and 2 collagen-binding domains (CBD) S3a (997-1003) and S3b (1008-1118) (PubMed:9922257, PubMed:11121400). The S1 domain has collagen hydrolytic activity (PubMed:11121400, PubMed:18937627). The metalloprotease S1 domain is composed of 3 subdomains which together resemble a saddle; an activator domain (residues 119-388), the catalytic peptidase subdomain (398-670) and a helper subdomain (679-790) joined by a Gly-rich hinge (387-397) (PubMed:21947205, PubMed:23703618). The S2 domain (799-880, PKD) is flexible within a larger structure (S1 plus S2, residues 119-880) (PubMed:21947205, PubMed:21871007). Binding to Ca(2+) renders the midsection of S2 more flexible; Ca(2+) binding confers thermostability (PubMed:25760606). S3a and S3b each have collagen-binding activity; collagen is bound more efficiently when both S3a and S3b are present (PubMed:11121400). CBD S3a plus S3b binds to many types of collagen in vitro and in vivo (PubMed:11913772). The structure of CBD S3b becomes more compact and thermostable when it is bound to Ca(2+) and its N-terminal linker (approximately residues 1008-1020) changes from an extended alpha-helix to a beta-sheet anchored to the rest of the CBD (PubMed:12682007, PubMed:23144249). S3b may act as a Ca(2+)-activated molecular switch to trigger domain reorientation (PubMed:12682007). Isolated CBD S3b binds unidirectionally to the C-terminus of the collagen triple helix via a surface cleft (PubMed:19208618, PubMed:23144249). The S3b domain binds preferentially to undertwisted segions of collagen (PubMed:22898990). Upon purification gives 67 kDa, 78 kDa, 82 kDa and 116 kDa (full-length) proteins all of which have the same N-terminus; only the longest form digests insoluble collagen (PubMed:9922257). At least 2 in vivo isolated forms (C1b and C1c) are missing the second collagen-binding domain, ending on Lys-1006 and Lys-1018 respectively (PubMed:22099748). Widely used for tissue dissociation due to their potent activity on connective tissue. A mix of ColG and ColH is used for isolation of pancreatic islet cells for subsequent transplantation. A mix of ColG and ColH has been used to allow release of retained placenta in cows and mares, and its use in humans has been proposed. N-aryl mercaptoacetamide-based inhibitors with submicromolar affinity for clostridial collagenases but negligibile activity on human collagenases have been discovered that may lead to promising anti-infective drugs against Clostridia (PubMed:28820255). SANTYL Ointment (Smith and Nephew, Inc.) is indicated for debriding chronic dermal ulcers and severely burned areas. It is unclear which of the collagenases from this bacteria is in the ointment. Xiaflex (Endo Pharmaceuticals, Inc.) is a mix of H.histolytica collagenases (ColG and ColH) used to treat both Dupuytren disease and Peyronie disease. Dupuytren disease is a progressive genetic disorder of pathologic collagen production and deposition under the skin of the hand that causes the fingers to be drawn into the palm, leading to flexion contractures of the joints, which can severely limit hand function. Injections of collagenase reduce these joint contractures (PubMed:10913202, PubMed:19726771). Peyronie disease (PD) is characterized by a disorganized, excessive deposition of collagen that forms a plaque within the penis. The plaque restricts lengthening on the affected side during erection, which can lead to penile curvature deformity, discomfort and erectile dysfunction, and can eventually lead to psychosocial effects such as depression and relationship difficulties. Studies have shown the clinical efficacy of collagenase injection for reducing penile curvature deformity and psychosocial symptoms (PubMed:8417217, PubMed:25711400). Clostridial collagenases enable the bacteria to infiltrate and colonize host tissue, and contribute to gas gangrene (myonecrosis) pathogenesis. Belongs to the peptidase M9B family. Collagenase subfamily.