Components of the organic matrices of rabbit incisor and molar dentine isolated after digestion of the demineralized tissues with collagenase.
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Latent pig synovial collagenase (EC 3.4.24.7) can be activated by a variety of different treatments to give an active enzyme form of lower molecular weight which rapidly degrades collagen. Trypsin and plasmin effectively activated the latent collagenase whilst elastase and cathepsin G degraded most of the latent enzyme before it was activated. A number of mercurials were compared and maximum activation was achieved using 4-aminophenylmercuric acetate and phenylmercuric chloride. The latent collagenase bound to a mercurial-Sepharose column and was eluted in the active form with NaCl. The latent collagenase also activated spontaneously and the conditions which encouraged and prevented this activation were studied. High NaCl concentration, diisopropylphosphofluoridate, soybean trypsin inhibitor, low Zn2+ concentration and high and low pH all prevented the spontaneous activation of latent pig synovial collagenase.
Collagenase harvested in vitro from rabbit alveolar macrophages eluted in gel chromatography corresponding to apparent molecular weights of 45 000, 85 000, and 165 000. Reversible changes from one molecular weight to another in low salt concentration and predominance of the 45 000 species in salt concentrations above 1.0 M (NaCl, KCl) suggest that the higher molecular weights represent polymeric forms of collagenase.
The ketone cinnamoyl-(1-13C-Phe)-CGly-Pro-Pro [(4-13C-5-cinnamido-4-oxo-6-phenylhexanoyl)-Pro-Pro 2] competitively inhibits a mixture of collagenases from Clostridium histolyticum with a Ki of 40 +/- 6 nM. 13C-nmr spectroscopy of the ketone in the presence of this collagenase shows a bound 13C resonance at 102.6 ppm and the resonance of the free ketone at 212 ppm. Ketone alone shows no trace (less than 0.5%) of a resonance in the region around 100 ppm. The bound resonance is displaceable by another competitive inhibitor. This ketone is thus a transition state analog which is rehybridized from trigonal planar to tetrahedral upon binding to collagenase.
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Gelatin zymograms revealed in human plasma a constant 66 kDa proteolytically active polypeptide. In most plasma samples other major proteolytic activities were seen at Mr 92,000, 130,000 and 225,000. All four proteases were Ca2+-dependent metalloproteases and bound quantitatively to gelatin-Sepharose. Immunoblotting results indicated that the 66 kDa protease was the human fibroblast gelatinase/type IV procollagenase and that the other three proteases were macrophage/granulocyte-derived gelatinase components. The 66 kDa protease did not bind to conA- nor lentil lectin-Sepharose allowing its separation from the 92, 130 and 225 kDa proteases. During the isolation procedure the plasma gelatinase/type IV procollagenase tended to form a proteolytically active spontaneous disulfide-bonded dimer and a 62 kDa component that could also be obtained by digestion with trypsin. The same polypeptide changes occurred also in stored preparations of the corresponding protease isolated from fibroblast culture medium while the freshly purified protein contained only the 66 kDa proform.
A series of synthetic peptide substrates for vertebrate collagenase having the structure Ac-Pro-Leu-Gly-X-Leu-Gly-OC2H5, where X is Leu, Ile, Val, Phe and Ala, have been prepared. Collagenolytic enzymes from various sources cleave these substrates with differing relative rate patterns. This series of peptides should be valuable for characterization of collagenases.
Collagenase is a potential virulence factor shown to be expressed by Porphyromonas gingivalis associated with periodontal disease. The purpose of this study was to use the polymerase chain reaction (PCR) to detect the presence of the collagenase gene (prtC) in 21 strains of Porphyromonas species isolated from endodontic infections. Type strains for P. gingivalis (ATCC 33277), P. endodontalis (ATCC 35406), Prevotella intermedia (ATCC 25611), and Prevotella nigrescens (ATCC 33563) were used as controls. When PCR primers specific for the 16S ribosomal RNA gene of P. gingivalis or P. endodontalis were used, 16 of the strains were identified as P. gingivalis, and five strains were identified as P. endodontalis. The presence of the prtC gene for collagenase was detected using PCR. Amplicons were analyzed by agarose gel electrophoresis, with an 815 bp amplicon representing the presence of the collagenase gene. Type strain ATCC 33277 and all 16 clinical isolates of P. gingivalis produced the collagenase gene amplicon. Neither type strain ATCC 35406 nor the five strains from clinical isolates of P. endodontalis produced the collagenase gene amplicon. These results indicate that P. gingivalis from endodontic infections possesses the prtC gene. P. endodontalis does not seem to exhibit prtC. The virulence of P. gingivalis may be related to its production of collagenase.
The cDNA that encodes the proenzyme form of human fibroblast collagenase has been expressed in Escherichia coli. It has been shown by a number of criteria to be functionally identical with the enzyme isolated from human sources. Mutations of each of three cysteine residues found in procollagenase were constructed by site-directed mutagenesis of the cDNA. The relative activities of these mutants were compared to the wild-type enzyme. All of the mutants retained proteolytic activity, but not necessarily on collagen. Mutations that interfere with the formation of the sulfhydryl bridge in the carboxy-terminal domain in some cases increased and in other cases decreased the rate of casein cleavage. On the basis of extensive autolysis within E. coli of a mutant with a replacement of cysteine-73, the procollagenase molecule produced appeared to be either spontaneously active or perhaps more susceptible to autolytic activation, despite the continued presence of the propeptide. Experiments designed to capture the active forms of the mutant by use of the irreversible inhibitor alpha 2-macroglobulin showed that some degree of latency still persisted in the autolytic mutant. These findings suggest that the cysteine at position 73 is important for maintaining the proenzyme in an inactive state but that the maintenance of latency in MMPs may be a complex process, involving a number of interactions between the propeptide domain and the remainder of the collagenase molecule.
The six collagenases (alpha, beta, gamma, delta, epsilon, and zeta) from Clostridium histolyticum isolated in the preceding paper [Bond, M. D., & Van Wart, H. E. (1984) Biochemistry (first paper of three in this issue)] have been characterized in detail. The molecular weights determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis range from 68 000 to 125 000. Isoelectric focusing experiments demonstrate that the isoelectric points of the collagenases are in the 5.35-6.20 range. These experiments also reveal that the subspecies of alpha- and gamma-collagenases (alpha1 vs. alpha 2 and gamma 1 vs. gamma 2) have different isoelectric points but the same molecular weights. Microheterogeneity is also observed for the beta- and epsilon-collagenases. The amino acid compositions of all six collagenases have been determined, and analysis for neutral sugars and hexosamines shows that none of the enzymes have a significant carbohydrate content. Zinc and calcium are the only metals that copurify with the collagenases. The purified enzymes contain approximately 1 mol of zinc/mol of protein and a calcium content that varies from about 2 mol/mol for alpha-collagenase to about 7 mol/mol for beta-collagenase. All of the collagenases are 5-10 times more active against gelatin than collagen. The alpha-, beta-, and gamma-collagenases are significantly less active toward the synthetic peptide substrates examined than the delta-, epsilon, and zeta-collagenases. This property, taken together with data on the stabilities and amino acid compositions of these enzymes, strongly supports their assignment to two distinct classes. This establishes clearly that C. histolyticum does, indeed, produce more than one different type of collagenase.
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1. Properties of a purified chemically activated form of pig synovial collagenase were examined and compared with a spontaneously active form of the enzyme. 2. The active enzyme has a specific activity of 53 000 units (microgram/min)/mg, a mol.wt. of 44 000 (by sodium dodecyl sulphate/polyarcylamide-gel electrophoresis in 2-mercaptoethanol) and pI 5.2 (by isoelectric focusing in polyacrylamide gels). 3. The activity has the characteristics of a metalloproteinase that degrades types I and III soluble or insoluble collagens in preference to type II, at an optimum pH of 6.5-8.5. 4. There is no detectable difference in these properties between the chemically activated and spontaneously active form of collagenase.
Culture medium from rabbit uterine cervical fibroblasts contained a procollagenase and a neutral proproteinase which acts as a procollagenase activator. These two proenzymes have been purified by a combination of ion-exchange, affinity and gel chromatographies. The purified neutral proproteinase showed Mr 60,000 with sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. This neutral proproteinase was activated by trypsin, 4-aminophenylmercuric acetate (APMA) and plasmin, and the active species of the proteinase had Mr 53,000 when activated by APMA; kallikrein and urokinase did not activate this proproteinase. The purified neutral proteinase was inhibited by EDTA, 1,10-phenanthroline and rabbit plasma, but not by serine proteinase inhibitors, suggesting that this proteinase is a metal-dependent proteinase. The purified enzyme could also degrade gelatin, casein, proteoglycan and type IV procollagen. The purified procollagenase had Mr 55,000 and was activated by trypsin, APMA and the active neutral proteinase. These activations were accompanied by decrease in Mr, and the activated species had an Mr which was approx. 10,000 less than that of the procollagenase. In particular, procollagenase activation with neutral proteinase depended on incubation time and proteolytic activity of proteinase. These results indicate that activation of procollagenase by the rabbit uterine neutral proteinase is related to limited proteolysis in the procollagenase molecule.
The latent forms of stromelysin and collagenase from human gingival fibroblasts were purified to homogeneity. These latent proenzymes underwent serial small reductions in Mr upon activation by treatment with either 4-aminophenylmercuric acetate or trypsin. Similar shifts in Mr and activation kinetics were observed upon identical treatments of either recombinant prostromelysin or procollagenase. Prostromelysin showed a lag between activation and Mr fall, suggesting an initial activation by conformational change. Collagenase activity was enhanced up to 12-fold by either natural or recombinant stromelysin in the presence of trypsin or 4-aminophenylmercuric acetate. Stromelysin caused a further apparent decrease in the Mr of procollagenase. Since these important connective-tissue-degrading enzymes are usually co-ordinately produced by cells, a cascade mechanism is proposed in which collagenase is activated by stromelysin.
The peptide derivative N alpha-(2,4-dinitrophenyl)-L-prolyl-L-leucyl-glycyl-L-prolyl-L-tryptophanyl-D- lysine (Dnp-Pro-Leu-Gly-Pro-Trp-D-Lys) has been found to be a convenient substrate for the assay of clostridial collagenase and Pz-peptidase. The substrate shows a 25-fold enhancement of fluorescence (gamma ex. 283 nm, lambda em. 350 nm) following hydrolysis of the Leu2-Gly3 peptide bond. The value of Km for clostridial collagenase was 17 microM. The substrate for the first time makes possible continuous fluorimetric assays for Pz-peptidase and clostridial collagenase.