Purification of Matrixins from Marine Cephalopod.

Matrixins play a major role in tissue regeneration and also in various patho-physiological processes. Discovery of matrix metallo proteins (MMPs) and their detailed structural and functional analysis would lead to the development of numerous potent synthetic inhibitors of matrixins to treat certain diseases. In the present investigation, a marine cephalopod- Octopus sp. collected from Cochin, in the south western Indian Ocean was used as animal model for purification of matrixins. The measurements, count, indices and other morphometric characters were noted down before assessing the presence of matrixins in the crude extract of Octopus samples. Purification of matrixins was carried out employing gel filtration chromatography and the purified matrixins was confirmed by gelatin zymogram. The purity of the protein was checked by both native and SDS-PAGE. The studies have provided clear indications of production of MMPs or matrixins with gelatinolytic activity in Octopus sp.

Expression and Purification of a Matrix Metalloprotease Transmembrane Domain in Escherichia coli.

Membrane tethered matrix metalloproteases are bound to the plasma membrane by a glycosylphosphatidylinositol-anchor or a transmembrane domain. To date, most studies of membrane-bound matrix metalloprotease have focused on the globular catalytic and protein-protein interaction domains of these enzymes. However, the transmembrane domains have been poorly studied even though they are known to mediate intracellular signaling via interaction with various cellular proteins. The expression and purification of the transmembrane domain of these proteins can be challenging due to their hydrophobic nature. In this chapter we describe the purification of a transmembrane domain for a membrane-bound matrix metalloprotease expressed in E. coli and its initial characterization by NMR spectroscopy.

Isolation and characterization of chicken bile matrix metalloproteinase.

Avian bile is rich in matrix metalloproteinases (MMP), the enzymes that cleave extracellular matrix proteins such as collagens and proteoglycans. Changes in bile MMP expression have been correlated with hepatic and gall bladder pathologies, but the significance of their expression in normal, healthy bile is not understood. We hypothesized that the MMP in bile may aid the digestion of native collagens that are resistant to conventional gastric proteases. Hence, the objective of this study was to characterize the bile MMP and check its regulation in association with dietary factors. We used substrate zymography, azocoll protease assay, and gelatin affinity chromatography to identify and purify the MMP from chicken bile. Using zymography and SDS PAGE, 5 bands at 70, 64, 58, 50, and 42 kDa were detected. The bands corresponding to 64, 50, and 42 kDa were identified as MMP2 using trypsin in-gel digestion and matrix-assisted laser desorption time-of-flight mass spectrometry and peptide mass fingerprinting. Chickens fed diets containing gelatin supplements showed higher levels of MMP expression in the bile by both azocoll assay and zymography. We conclude that the bile MMP may be associated with the digestion of collagens and other extracellular matrix proteins in avian diets.

Purification and characterization of a gelatinolytic matrix metalloproteinase from the skeletal muscle of grass carp (Ctenopharyngodon idellus).

A gelatinolytic matrix metalloproteinase (gMMP) from grass carp skeletal muscle was purified by 30-70% ammonium sulphate fractionation and a combination of chromatographic steps including ion exchange on DEAE-Sephacel, gel filtration on Sephacryl S-200, and affinity on gelatin-sepharose. The molecular weight of the proteinase as estimated by SDS-PAGE was 70 kDa under non-reducing conditions. The enzyme revealed high activity from 30 to 50 °C, and the gelatin hydrolysing activity was investigated at a slightly alkaline pH range using gelatin as substrate. Metalloproteinase inhibitor EDTA completely suppressed the gelatinolytic activity, while other proteinase inhibitors did not show any inhibitory effect. Divalent metal ion Ca(2+) was essential for the gelatinolytic activity. Further, peptide mass fingerprinting obtained four fragments with 45 amino acid residues, which were highly identical to MMP-2 from fish species. The gMMP could effectively hydrolyse type I collagen even at 4 °C, suggesting its involvement in the texture softening of fish muscle during the post-mortem stage.

A recombinant matrix metalloproteinase protein from Gnathostoma spinigerum for serodiagnosis of neurognathostomiasis.

Neurognathostomiasis is a severe form of human gnathostomiasis which can lead to disease and death. Diagnosis of neurognathostomiasis is made presumptively by using clinical manifestations. Immunoblotting, which recognizes antigenic components of molecular mass 21 kDa and 24 kDa in larval extracts of Gnathostoma spinigerum (Gs 21/24), has high sensitivity and specificity for diagnosis of neurognathostomiasis. However, only very small amounts of the Gs 21/24 antigens can be prepared from parasites harvested from natural or experimental animals. To overcome this problem, we recently produced a recombinant matrix metalloproteinase (rMMP) protein from G. spinigerum. In this study, we evaluated this rMMP alongside the Gs 21/24 antigens for serodiagnosis of human neurognathostomiasis. We studied sera from 40 patients from Srinagarind Hospital, Khon Kaen University, Thailand, with clinical criteria consistent with those of neurognathostomiasis, and sera from 30 healthy control adults from Thailand. All sera were tested for specific IgG antibodies against both G. spinigerum crude larval extract and rMMP protein using immunoblot analysis. The sensitivity and specificity for both antigenic preparations were all 100%. These results show that G. spinigerum rMMP protein can be used as an alternative diagnostic antigen, in place of larval extract, for serodiagnosis of neurognathostomiasis.

Identification and characterization of an amphioxus matrix metalloproteinase homolog BbMMPL2 responding to bacteria challenge.

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases mainly involved in extracellular matrix (ECM) degradation. We have cloned and identified BbMMPL2 as homolog of MMPs from adult amphioxus. Recombinant BbMMPL2 proteins underwent self-processing during refolding in vitro. The final ~23 kDa polypeptide displayed proteolytic activity against ECM components like casein, gelatin, collagen IV and fibrinogen, but not laminin, fibronectin or α1-PI. This activity could be inhibited by GM6001 and TIMP-1/2. In addition, real-time RT-PCR analysis revealed that BbMMPL2 expressed in all issues/organs in adult amphioxus we tested. Its transcription was significantly up-regulated 12 h post immune challenge by Escherichia coli in epidermis and hepatic diverticulum but only slightly increased by Staphyloccocus aureus in epidermis. Furthermore, recombinant BbMMPL2-EGFP expressed in 293T and NIH/3T3 cells showed aggregation in cytoplasm and induced cell death. Our results provided new evidence that MMP was involved in immune response which could be conserved through evolution.

A metalloproteinase karilysin present in the majority of Tannerella forsythia isolates inhibits all pathways of the complement system.

Tannerella forsythia is a poorly studied pathogen despite being one of the main causes of periodontitis, which is an inflammatory disease of the supporting structures of the teeth. We found that despite being recognized by all complement pathways, T. forsythia is resistant to killing by human complement, which is present at up to 70% of serum concentration in gingival crevicular fluid. Incubation of human serum with karilysin, a metalloproteinase of T. forsythia, resulted in a decrease in bactericidal activity of the serum. T. forsythia strains expressing karilysin at higher levels were more resistant than low-expressing strains. Furthermore, the low-expressing strain was significantly more opsonized with activated complement factor 3 and membrane attack complex from serum compared with the other strains. The high-expressing strain was more resistant to killing in human blood. The protective effect of karilysin against serum bactericidal activity was attributable to its ability to inhibit complement at several stages. The classical and lectin complement pathways were inhibited because of the efficient degradation of mannose-binding lectin, ficolin-2, ficolin-3, and C4 by karilysin, whereas inhibition of the terminal pathway was caused by degradation of C5. Interestingly, karilysin was able to release biologically active C5a peptide in human plasma and induce migration of neutrophils. Importantly, we detected the karilysin gene in >90% of gingival crevicular fluid samples containing T. forsythia obtained from patients with periodontitis. Taken together, the newly characterized karilysin appears to be an important virulence factor of T. forsythia and might have several important implications for immune evasion.

Production and characterization of a novel extracellular metalloproteinase by a newly isolated moderate halophile, Halobacillus sp. LY6.

A moderately halophilic bacterium LY6 with high proteolytic activity was isolated. Biochemical and physiological characterization, along with 16S rDNA sequence analysis placed the isolate in the genus Halobacillus. The salinity of the culture medium strongly influenced the proteinase production of LY6. Maximum enzyme production was observed in the medium containing 5% Na(2)SO(4) or 10% NaCl. Proteinase production was synchronized with bacterial growth and reached a maximum level during the mid-stationary phase. Enzyme purification was carried out by a simple approach including a combination of ammonium sulfate precipitation and Sephacryl S-100 gel filtration chromatography. SDS-PAGE and gelatin zymography analysis revealed it was a monomer with high molecular weight of 69 kDa. Optimal proteinase activity was obtained at pH 10.0, 40°C, and 10% NaCl. It was high active over broad temperature (30-80°C), pH (6.0-12.0), and NaCl concentration (0-25%) ranges, indicating its thermostable, alkali-stable, and halotolerant nature. Moreover, the enzyme activity was markedly enhanced by Ca(2+) and Cu(2+), but strongly inhibited by EDTA, PAO, and DEPC, indicating that it probably was a metalloproteinase with cysteine and histidine residues located in its active site.

La matriz extracelular: de la mecánica molecular al microambiente tumoral (parte II) / The extracellular matrix: From the molecular mechanics to the tumoral microenvironment (part II)

IntroducciónLa matriz extracelular (MEC) representa una red tridimensional que engloba todos los órganos, tejidos y células del organismo. Constituye un filtro biofísico de protección, nutrición e inervación celular y el terreno para la respuesta inmune, angiogénesis, fibrosis y regeneración tisular. También representa el medio de transmisión de fuerzas mecánicas a la membrana basal, que a través de las integrinas soporta el sistema de tensegridad y activa los mecanismos epigenéticos celulares.Método y resultadosLa revisión de la literatura y actualización del tema muestran como la alteración de la MEC supone la pérdida de su función de filtro eficaz, nutrición, eliminación, denervación celular, pérdida de la capacidad de regeneración y cicatrización y alteración de la transmisión mecánica o mecanotransducción. También la pérdida del sustrato para una correcta respuesta inmune ante agentes infecciosos, tumorales y tóxicos.Método y resultadosEsta segunda parte de revisión de la MEC considera los tumores como tejidos funcionales conectados y dependientes del microambiente. El microambiente tumoral, constituido por la MEC, células del estroma y la propia respuesta inmune son determinantes de la morfología y clasificación tumoral, agresividad clínica, pronóstico y respuesta al tratamiento del tumor.ConclusiónTanto en condiciones fisiológicas como patológicas, la comunicación recíproca entre células del estroma y el parénquima dirige la expresión génica. La capacidad oncogénica del estroma procede tanto de los fibroblastos asociados al tumor como de la celularidad de la respuesta inmune y la alteración de la tensegridad por la MEC. La transición epitelio-mesenquimal es el cambio que transforma una célula normal o «benigna» en «maligna»...(AU)

IntroductionThe extracellular matrix (ECM) is a three-dimensional network that envelopes all the organs, tissues and cells of the body. A biophysical filter that provides protection, nutrition and cell innervation, it is the site for the immune response, angiogenesis, fibrosis and tissue regeneration. It is also the transport medium for mechanical forces to the basal membrane through integrins that support the tensegrity system, activating cellular epigenetic mechanisms.Method and resultsThe review of the literature shows how the disruption of the ECM leads to a functional loss of nutrition, elimination, cell innervation, regenerative capacity and wound healing as well as alterations in mechanical transduction. This loss also disrupts the immune response to pathogens, tumour cells and toxins.Method and resultsThe second part of our revision of the ECM considers tumours as interconnected, functional tissues dependant on their microenvironment. The tumoural microenvironment, which is comprised of the ECM, stromal cells and the immune response, determines the morphology of the tumour and its classification as well as its clinical aggressivity, prognosis and response to treatment.ConclusionsBoth in physiological and pathological conditions, the reciprocal communication between the cells of the stroma and the parenchyma direct the genetic expression. The onocogenic capacity of the stroma depends not only on the fibroblasts associated with the tumour but also on the cellularity of the immune response and the alteration in the tensegrity model of the ECM. The epithelial-mesenchymal transition is the change which transforms a normal, or benign, cell into a malignant one. The “pseudomesenchymal” cytoskeleton provides the properties of migration, invasion and dissemination, and vice-versa: the malignant phenotype is reversible by correction of the key factors that create the tumoural microenvironment(AU)

Expression and activity profiling of selected cysteine cathepsins and matrix metalloproteinases in synovial fluids from patients with rheumatoid arthritis and osteoarthritis.

Cysteine cathepsins and matrix metalloproteases are considered to play important roles in the development of arthritic diseases. Their accumulation in synovial fluid of primarily rheumatoid arthritis patients is also well documented. However, a detailed comparison between the protease levels and activities between rheumatoid arthritis samples and osteoarthritis samples has never been made. Here, we report that both cysteine cathepsins B and S and matrix metalloproteases-1, -3 and -13 are detected in patient synovial fluid samples with significantly higher levels detected in rheumatoid arthritis patients. Among the proteases, cathepsin S was found to be significantly elevated, consistent with its critical role in the immune response. These results suggest that cysteine cathepsins have a major role in inflammation at least in rheumatoid arthritis. In addition to proteases, interleukin-6 was detected at significant levels in most samples, suggesting that proinflammatory cytokines might be in-volved in the stimulation of expression of these proteases during inflammation.

Expression of recombinant matrix metalloproteinases in Escherichia coli.

Matrix metalloproteinases (MMPs) are a group of zinc-dependent endopeptidases that are capable of cleaving all of the components of the extracellular matrix (ECM). The role that the MMPs play in normal and pathological conditions has long been of interest. The mechanisms by which the MMPs cleave the different components of the ECM have been examined extensively. Some of these studies have been made possible, in part, by the ability to express recombinant MMPs. These recombinant MMPs have been utilized in both structural and functional studies. In addition, future studies can benefit from the availability of recombinant MMPs. Recombinant MMPs have been expressed in mammalian and bacterial recombinant expression systems. The most common bacterial expression system employed for this has been the utilization of expression plasmids in Escherichia coli. This has resulted in the production of a large amount of protein in a short period of time. The expression of a recombinant truncated form of human stromelysin-1 (MMP-3) will be used to illustrate the methods utilized for the expression of a MMP in E. coli. This will include discussions about the expression vector, the cloning of the MMP cDNA into the expression vector, protein induction, protein extraction, protein refolding and purification, and protein characterization.

A novel matrix metalloprotease-like enzyme (karilysin) of the periodontal pathogen Tannerella forsythia ATCC 43037.

Proteases of Tannerella forsythia, a pathogen associated with periodontal disease, are implicated as virulence factors. Here, we characterized a matrix metalloprotease (MMP)-like enzyme of T. forsythia referred to as karilysin. Full-length (without a signal peptide) recombinant karilysin (49.9 kDa) processed itself into the mature 18-kDa enzyme through sequential autoproteolytic cleavage at both N- and C-terminal profragments. The first cleavage at the Asn14-Tyr15 peptide bond generated the fully active enzyme (47.9 kDa) and subsequent truncations at the C-terminus did not affect proteolytic activity. Mutation of Tyr15 to Ala generated a prokarilysin variant that processed itself into the final 18-kDa form with greatly reduced kinetics. Inactive prokarilysin with the mutated catalytic Glu residue (E136A) was processed by active karilysin at the same sites as the active enzymes. Karilysin proteolytic activity and autoprocessing were inhibited by 1,10-phenanthroline and EDTA. Calcium ions were found to be important for both the activity and thermal stability of karilysin. Using CLiPS technology, the specificity of karilysin was found to be similar to that of MMPs with preference for Leu/Tyr/Met at P1' and Pro/Ala at P3. This specificity and the ability to degrade elastin, fibrinogen and fibronectin may contribute to the pathogenicity of periodontitis.

Prevention of ischemia/reperfusion-induced accumulation of matrix metalloproteinases in rat lung by preconditioning with nitric oxide.

BACKGROUND: Pulmonary ischemia/reperfusion (I/R) injury is associated with degradation of structural proteins. Preconditioning by short-term inhalation of nitric oxide (NO) ameliorates some of the severe consequences of an I/R cycle. The aim of this study was to evaluate the effects of NO preconditioning on I/R-induced changes of matrix metalloproteinase (MMP) activity. MATERIALS AND METHODS: Left lung in situ ischemia in rats was maintained for 1 h, followed by reperfusion for 30 min or 4 h. In the NO group, animals inhaled NO (15 ppm) for 10 min directly before ischemia. Changes of expression or activity of MMPs (MMP-2, MMP-7, MMP-9, MMP-14) and of neutrophil elastase (NE) in bronchoalveolar lavage fluid (BALF), lung tissue, and arterial plasma were analyzed by zymography and Western blotting. Western blotting was also used to detect tissue inhibitors of matrix proteases, the extracellular metalloproteinase inducer (EMMPRIN or CD147), and endostatin, a proteolytic collagen fragment. RESULTS: Ischemia resulted in an increase of lavagable MMP activity (12.3-fold MMP-2, 8.1-fold MMP-7) at 30 min reperfusion. The activity of MMP-9 and NE in lung tissue progressively increased with time, whereas MMP-14 and MMP-2 were constant. Inhalation of NO prevented the early increase of MMP-2 and MMP-7 in BALF, but the level of MMP-9 and NE in tissue was not affected. The expression of tissue inhibitors of matrix proteases and EMMPRIN did not respond to any treatment. The release of endostatin proceeded in parallel to the level of MMPs in BALF. Significant correlations between MMP-9 and myeloperoxidase in lung tissue and between MMP-2/MMP-7 and plasma protein extravasation were found. CONCLUSIONS: The early rise of MMP-2 and MMP-7 in BALF resulted from plasma protein extravasation, whereas MMP-9 and NE were imported into lung tissue via leukocyte invasion. The effect of NO inhalation on lavagable MMPs was secondary to the sealing of the permeability barrier.

Purification of matrix metalloproteinases by column chromatography.

Matrix metalloproteinases (MMPs) are zinc endopeptidases composed of 23 members in humans, which belong to a subfamily of the metzincin superfamily. They play important roles in many pathophysiological events including development, organogenesis, angiogenesis, tissue remodeling and destruction, and cancer cell proliferation and progression by degradation of extracellular matrix (ECM) and non-ECM proteins and interaction with various molecules. Here, we present standard protocols for purification of native proMMPs (proMMP-1, -2, -3, -7, -9 and -10) and recombinant MT1-MMP (MMP-14) using conventional column chromatography. Purification steps comprise the initial common step [diethylaminoethyl (DEAE)-cellulose, Green A Dyematrex gel and gelatin-Sepharose columns], the second step for removal of nontarget proMMPs by immunoaffinity columns (anti-MMP-1 and/or anti-MMP-3 IgG-Sepharose columns) and the final step for further purification (IgG-Sepharose, DEAE-cellulose, Zn2+-chelate-Sepharose and/or gel filtration columns). Purified proMMPs and MMP are functionally active and suitable for biochemical analyses. The basic protocol for the purification from culture media takes approximately 7-10 d.

Neural MMP-28 expression precedes myelination during development and peripheral nerve repair.

Mammalian matrix metalloproteinase 28 (MMP-28) is expressed in several normal adult tissues, and during cutaneous wound healing. We show that, in frog and mouse embryos, MMP-28 is expressed predominantly throughout the nervous system. Xenopus expression increases during neurulation and remains elevated through early limb development where it is expressed in nerves. In the mouse, neural expression peaks at embryonic day (E) 14 but remains detectable through E17. During frog hindlimb regeneration XMMP-28 is not initially expressed in the regenerating nerves but is detectable before myelination. Following hindlimb denervation, XMMP-28 expression is detectable along regenerating nerves before myelination. In embryonic rat neuron-glial co-cultures, MMP-28 decreases after the initiation of myelination. Incubation of embryonic brain tissue with purified MMP-28 leads to the degradation of multiple myelin proteins. These results suggest that MMP-28 plays an evolutionarily conserved role in neural development and is likely to modulate the axonal-glial extracellular microenvironment.

Characterization of matrix metalloproteinase expressed by human embryonic kidney cells.

There is little information available on the proteases expressed by human embryonic kidney (HEK) cells, which are often used for expression of recombinant proteins and production of adenovirus vector. The expression profile of proteases in HEK cell line was investigated using zymography, mRNA analysis, western blotting and protein array. The major protease was gelatinase A [or matrix metalloproteinase (MMP)-2]. Beside, other MMPs, such as MMP-1, -2, -3, -8, -9, -10, -13 and membrane type (MT) 1- and 3-MMP, as well as tissue inhibitors of metalloproteinase (TIMP)-1, -2 and -3, were also expressed by HEK cells. Characterization of MMP and TIMP profiles expressed by HEK cells provides the basis for degradation control of recombinant protein and adenovirus vector during culture and purification processes.

Mapping and partial characterization of proteases expressed by a CHO production cell line.

The proteolytic activities expressed by a Chinese hamster ovary (CHO) cell line in the cultivation supernatant during the production of recombinant factor VIII were mapped with a broad spectrum protease assay and a series of different types of protease inhibitors. The destabilizing effect on the product emanated from a metalloproteinase, which could be effectively blocked by chelating agents to lead to product stabilization. Amino acid sequences of the isolated metalloproteinase were found to have sequence homology with matrix metalloproteinases (MMPs) MMP3, MMP10, and MMP12. Several species with metalloproteinase activity were characterized and found to be related to each other. The results indicate that an MMP pro-enzyme of >/=200 kDa was released from the CHO cells during the production phase. The enzyme expressed collagenase/gelatinase activity when activated. Due to autoproteolysis, a number of smaller, less specific MMPs were formed with the smallest form, a 19.4 kDa protein, being the most active. These results may be of particular relevance for other production processes using CHO cells for the expression of recombinant proteins.

Characterization of a novel metalloproteinase in Duvernoy's gland of Rhabdophis tigrinus tigrinus.

During the characterization of hemorrhagic factor in venom of Rhabdophis tigrinus tigrinus, so-called Yamakagashi in Japan, one of the Colubridae family, a novel metalloproteinase with molecular weight of 38 kDa in the Duvernoy's gland of Yamakagashi was identified by gelatin zymography and by monitoring its proteolytic activity using a fluorescence peptide substrate, MOCAc-PLGLA2pr(Dnp)AR-NH2, which was developed for measuring the well-known matrix metalloproteinase (MMP) activity. After purification by gel filtration HPLC and/or column switch HPLC system consisting of an affinity column, which was immobilized with a synthetic BS-10 peptide (MQKPRCGVPD) originating from propeptide domain of MMP-7 and a reversed-phase column, the N-terminal amino acid sequence of the 38 kDa metalloproteinase was identified as FNTFPGDLK which shared a high homology to Xenopus MMP-9. The 38 kDa metalloproteinase required Zn2+ and Ca2+ ions for its proteolytic activity. In addition, the proteolytic activity was almost completely inhibited by BS-10, a MMP inhibitor, but not by the serine proteinase inhibitors, cysteine proteinase inhibitors and aspartic proteinase inhibitors. Together these results demonstrated that the 38 kDa proteinase is a novel snake verom metalloproteinase (SVMP) containing HExGHxxGxxH motif which possesses high affinity to the BS-10 peptide, into its molecule, and the enzymatic properties are closed to that of MMPs. Based on the results obtained in the present study, we concluded that the 38 kDa metalloproteinase is a novel metalloproteinase whose activity may be regulated by the cysteine switch mechanism, and could be classified as one of the matrix metalloproteinases rather than snake venom metalloproteinases.

Activity-based matrix metallo-protease enrichment using automated, inhibitor affinity extractions.

An automated inhibitor affinity extraction method for the activity-based enrichment of matrix metallo-proteases (MMPs) is presented. Samples containing purified MMP-12 were first extracted at different flow rates in a syringe pump setup, using cartridges packed with an MMP inhibitor affinity sorbent based on an immobilized hydroxamic acid containing peptide (PLG-NHOH) with mumol/L MMP affinity. Faster extractions, a reduced number of manual manipulations, and higher extraction yields (98.9%-99.3%) were obtained over the whole flow rate range compared to batch extractions. Application of the method to synovial fluid from a rheumatoid arthritis patient followed by gelatin-zymography revealed a strong enrichment of distinct MMPs from this biological sample that were not clearly visible in the original sample. The use of an auto-sampler and a solid-phase extraction (SPE) workstation allowed full automation of the extraction procedure with the potential for on-line coupling to further sample preparation and analytical steps. MMP-12 extractions were optimized showing that ligand density is an important factor with a clear extraction yield optimum around 5 to 7.5 mmol/L. Conditioning of the stationary phase for 1 week prior to use resulted in a further slight increase in extraction yield. Under optimal conditions, an extraction yield of 99.5% was reached with a cartridge contact time of only 13 s for MMP-12. The efficacy of the extraction method for activity-based MMP profiling was further improved by the use of a broad-spectrum MMP inhibitor with nmol/L affinity (TAPI-2). This resulted in an increased extraction yield for all tested MMPs. For MMP-1, -7, -8, -10, -12, and -13 extraction yields of at least 98.8% were obtained, while for MMP-9 (full length and catalytic domain) an extraction yield of at least 96.1% was reached.

MMP-20 is predominately a tooth-specific enzyme with a deep catalytic pocket that hydrolyzes type V collagen.

Matrix metalloproteinase-20 (MMP-20, enamelysin) has a highly restricted pattern of expression. In healthy tissues, MMP-20 is observed in the enamel organ and pulp organ of developing teeth and is present only as an activated enzyme. To identify other tissues that may express MMP-20, we performed a systematic mouse tissue expression screen. Among the non-tooth tissues assayed, MMP-20 transcripts were identified only in minute quantities within the large intestine. The murine Mmp20 promoter was cloned, sequenced, and assessed for potential tooth-specific regulatory elements. In silico analysis identified four promoter modules that were common to Mmp20 and at least two of three coregulated predominantly tooth-specific genes that encode ameloblastin, amelogenin, and enamelin. We asked if the highly restricted MMP-20 expression pattern was associated with a broad substrate specificity that might preclude its expression in other tissues. An iterative mixture-based random doedecamer peptide library screen with Edman sequencing of MMP-20 cleavage products revealed that, among MMPs previously screened, MMP-20 had unique substrate preferences. These preferences indicate that MMP-20 has a deep and wide catalytic pocket that can accommodate substrates with large aromatic residues in the P1' position. On the basis of matrices derived from the peptide library data, we identified and then confirmed that type V collagen is an MMP-20 substrate. Since type V collagen is not present in dental enamel but is an otherwise widely distributed collagen, and since only active MMP-20 has been observed in teeth, our data suggest that control of MMP-20 activity is primarily regulated by transcriptional means.