87-412: 1MMQ , 1MMR , 2MZE , 2DDY , 2Y6C , 2MZH , 1MMP , 2Y6D 4316 17393 ENSG00000137673 ENSMUSG00000018623 P09237 Q10738 Q3UN27 NM_002423 NM_010810 NM_001319986 NP_002414 NP_001306915 NP_034940 Matrilysin also known as matrix metalloproteinase-7 (MMP-7), pump-1 protease (PUMP-1), or uterine metalloproteinase is an enzyme in humans that
174-487: A catalytic triad , stabilize charge build-up on the transition states using an oxyanion hole , complete hydrolysis using an oriented water substrate. Enzymes are not rigid, static structures; instead they have complex internal dynamic motions – that is, movements of parts of the enzyme's structure such as individual amino acid residues, groups of residues forming a protein loop or unit of secondary structure , or even an entire protein domain . These motions give rise to
261-489: A conformational ensemble of slightly different structures that interconvert with one another at equilibrium . Different states within this ensemble may be associated with different aspects of an enzyme's function. For example, different conformations of the enzyme dihydrofolate reductase are associated with the substrate binding, catalysis, cofactor release, and product release steps of the catalytic cycle, consistent with catalytic resonance theory . Substrate presentation
348-511: A type of enzyme rather than being like an enzyme, but even in the decades since ribozymes' discovery in 1980–1982, the word enzyme alone often means the protein type specifically (as is used in this article). An enzyme's specificity comes from its unique three-dimensional structure . Like all catalysts, enzymes increase the reaction rate by lowering its activation energy . Some enzymes can make their conversion of substrate to product occur many millions of times faster. An extreme example
435-433: A broad-spectrum MMP inhibitor, and cipemastat (Ro 32-3555), an MMP-1 selective inhibitor, have performed poorly in clinical trials . The failure of Marimastat was partially responsible for the folding of British Biotech , which developed it. The failure of these drugs has been due largely to toxicity (in particular, musculo-skeletal toxicity in the case of broad spectrum inhibitors) and failure to show expected results (in
522-471: A conserved C-terminal protein domain. The enzyme is involved in wound healing , and studies in mice suggest that it regulates the activity of defensins in intestinal mucosa . MMP7 was initially characterized by Woessner et al. It digests components of the extracellular matrix, cleaves the α 2 (I) chain of gelatin more rapidly, and digests the B chain of insulin at Ala-Leu and Tyr-Leu, and has no action on collagen types I, II, IV, V. The optimal pH of MMP7
609-476: A family of four protease inhibitors : TIMP-1, TIMP-2, TIMP-3, and TIMP-4. Synthetic inhibitors generally contain a chelating group that binds the catalytic zinc atom at the MMP active site tightly. Common chelating groups include hydroxamates , carboxylates , thiols , and phosphinyls . Hydroxymates are particularly potent inhibitors of MMPs and other zinc-dependent enzymes, due to their bidentate chelation of
696-474: A first step and then checks that the product is correct in a second step. This two-step process results in average error rates of less than 1 error in 100 million reactions in high-fidelity mammalian polymerases. Similar proofreading mechanisms are also found in RNA polymerase , aminoacyl tRNA synthetases and ribosomes . Conversely, some enzymes display enzyme promiscuity , having broad specificity and acting on
783-481: A larger family of proteases known as the metzincin superfamily . Collectively, these enzymes are capable of degrading all kinds of extracellular matrix proteins, but also can process a number of bioactive molecules. They are known to be involved in the cleavage of cell surface receptors , the release of apoptotic ligands (such as the FAS ligand ), and chemokine / cytokine inactivation. MMPs are also thought to play
870-690: A major role in cell behaviors such as cell proliferation , migration ( adhesion /dispersion), differentiation , angiogenesis , apoptosis , and host defense . They were first described in vertebrates in 1962, including humans, but have since been found in invertebrates and plants. They are distinguished from other endopeptidases by their dependence on metal ions as cofactors , their ability to degrade extracellular matrix, and their specific evolutionary DNA sequence . MMPs were described initially by Jerome Gross and Charles Lapiere in 1962, who observed enzymatic activity ( collagen triple helix degradation) during tadpole tail metamorphosis (by placing
957-464: A quantitative theory of enzyme kinetics, which is referred to as Michaelis–Menten kinetics . The major contribution of Michaelis and Menten was to think of enzyme reactions in two stages. In the first, the substrate binds reversibly to the enzyme, forming the enzyme-substrate complex. This is sometimes called the Michaelis–Menten complex in their honor. The enzyme then catalyzes the chemical step in
SECTION 10
#17328850872071044-439: A range of different physiologically relevant substrates. Many enzymes possess small side activities which arose fortuitously (i.e. neutrally ), which may be the starting point for the evolutionary selection of a new function. To explain the observed specificity of enzymes, in 1894 Emil Fischer proposed that both the enzyme and the substrate possess specific complementary geometric shapes that fit exactly into one another. This
1131-400: A shallow hydrophobic substrate-binding pocket. In contrast to MMP9 which has the longest hinge, MMP7 lacks hemopexin and does not have a hinge. Instead, MMP7 contains a variable C-terminal hemopexin-like domain facilitates substrate specificity. The protein of MMP7 is secreted as zymogen. The prodoamin of MMP7 contains an approximately 9 kD highly conserved “cysteine switch” PRCGXPD sequence near
1218-451: A species' normal level; as a result, enzymes from bacteria living in volcanic environments such as hot springs are prized by industrial users for their ability to function at high temperatures, allowing enzyme-catalysed reactions to be operated at a very high rate. Enzymes are usually much larger than their substrates. Sizes range from just 62 amino acid residues, for the monomer of 4-oxalocrotonate tautomerase , to over 2,500 residues in
1305-446: A steady level inside the cell. For example, NADPH is regenerated through the pentose phosphate pathway and S -adenosylmethionine by methionine adenosyltransferase . This continuous regeneration means that small amounts of coenzymes can be used very intensively. For example, the human body turns over its own weight in ATP each day. As with all catalysts, enzymes do not alter the position of
1392-434: A tadpole tail in a collagen matrix plate). Therefore, the enzyme was named interstitial collagenase ( MMP-1 ). Later, it was purified from human skin (1968), and was recognized to be synthesized as a zymogen . The "cysteine switch" was described in 1990. The MMPs have a common domain structure . The three common domains are the pro-peptide, the catalytic domain , and the haemopexin -like C-terminal domain, which
1479-442: A thermodynamically unfavourable one so that the combined energy of the products is lower than the substrates. For example, the hydrolysis of ATP is often used to drive other chemical reactions. Enzyme kinetics is the investigation of how enzymes bind substrates and turn them into products. The rate data used in kinetic analyses are commonly obtained from enzyme assays . In 1913 Leonor Michaelis and Maud Leonora Menten proposed
1566-457: Is k cat , also called the turnover number , which is the number of substrate molecules handled by one active site per second. The efficiency of an enzyme can be expressed in terms of k cat / K m . This is also called the specificity constant and incorporates the rate constants for all steps in the reaction up to and including the first irreversible step. Because the specificity constant reflects both affinity and catalytic ability, it
1653-838: Is orotidine 5'-phosphate decarboxylase , which allows a reaction that would otherwise take millions of years to occur in milliseconds. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, nor do they alter the equilibrium of a reaction. Enzymes differ from most other catalysts by being much more specific. Enzyme activity can be affected by other molecules: inhibitors are molecules that decrease enzyme activity, and activators are molecules that increase activity. Many therapeutic drugs and poisons are enzyme inhibitors. An enzyme's activity decreases markedly outside its optimal temperature and pH , and many enzymes are (permanently) denatured when exposed to excessive heat, losing their structure and catalytic properties. Some enzymes are used commercially, for example, in
1740-419: Is 49% homologous to stromelysin-1. Comparing to other members of MMP family, MMP7 does not have a C-terminal protein domain. The promoter of the human MMP7 contains a TATA box, an activator protein 1 (AP-1) site, and two inverted polyomavirus enhancer A-binding proteins 2 (PEA-3). The AP-1/PEA-3 binding motif is required and essential for MMP7 to be responsive to growth factors, oncogenes and phorbol ester. Also,
1827-421: Is a process where the enzyme is sequestered away from its substrate. Enzymes can be sequestered to the plasma membrane away from a substrate in the nucleus or cytosol. Or within the membrane, an enzyme can be sequestered into lipid rafts away from its substrate in the disordered region. When the enzyme is released it mixes with its substrate. Alternatively, the enzyme can be sequestered near its substrate to activate
SECTION 20
#17328850872071914-518: Is an oblate sphere measuring 35 x 30 x 30 Å (3.5 × 3 x 3 nm ). The active site is a 20 Å (2 nm) groove that runs across the catalytic domain. In the part of the catalytic domain forming the active site there is a catalytically important Zn ion, which is bound by three histidine residues found in the conserved sequence HExxHxxGxxH. Hence, this sequence is a zinc-binding motif. The gelatinases , such as MMP-2 , incorporate Fibronectin type II modules inserted immediately before in
2001-422: Is at 7 and the pI is at 5.9. MMP4 is inhibited by α 2-macroglobulin and TIMP. The inhibition of MMP7 activity commonly relies on metal-chelating agents including EDTA and 1,10-phenanthroline, especially zinc chelation. Therefore, the selectivity of MMP7 inhibition is challenging since almost all members of MMPs family contain catalytic domains with zinc binding sites. TIMP-1 and 2 noncovalently bound to active MMP7 at
2088-454: Is called enzymology and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules , also called ribozymes . They are sometimes described as
2175-437: Is described by "EC" followed by a sequence of four numbers which represent the hierarchy of enzymatic activity (from very general to very specific). That is, the first number broadly classifies the enzyme based on its mechanism while the other digits add more and more specificity. The top-level classification is: These sections are subdivided by other features such as the substrate, products, and chemical mechanism . An enzyme
2262-500: Is encoded by the MMP7 gene . The enzyme ( EC 3.4.24.23 ) has also been known as matrin , putative (or punctuated) metalloproteinase-1 , matrix metalloproteinase pump 1 , PUMP-1 proteinase , PUMP , metalloproteinase pump-1 , putative metalloproteinase , MMP ). Human MMP-7 has a molecular weight around 30 kDa. Matrilysin was discovered by Sellers and Woessner in the uterus of the rat in 1988. The complementary DNA (cDNA) of human MMP7
2349-647: Is found to potentially be involved in tumor metastasis and inflammatory processes. The upregulation of MMP7 is associated with many malignant tumors including esophagus, stomach, colon, liver, pancreas, and renal cell carcinomas. High MMP7 expression facilitates cancer invasion and angiogenesis by degrading extracellular matrix macromolecules and connective tissues. These degradations are associated with many mechanisms including embryogenesis, postpartum uterine involution, tissue repair, angiogenesis, bone remodeling, arthritis, decubitus ulcer, and tumor metastasis/invasion. Activated MMP7 activates MMP2 and MMP9 zymogens, and mediates
2436-749: Is fully specified by four numerical designations. For example, hexokinase (EC 2.7.1.1) is a transferase (EC 2) that adds a phosphate group (EC 2.7) to a hexose sugar, a molecule containing an alcohol group (EC 2.7.1). Sequence similarity . EC categories do not reflect sequence similarity. For instance, two ligases of the same EC number that catalyze exactly the same reaction can have completely different sequences. Independent of their function, enzymes, like any other proteins, have been classified by their sequence similarity into numerous families. These families have been documented in dozens of different protein and protein family databases such as Pfam . Non-homologous isofunctional enzymes . Unrelated enzymes that have
2523-462: Is highly expressed in the luminal surface of dysplastic glands in human colorectal cancers. A MMP7 protein is bounded by four metal ions including a catalytic zinc ion, a structural zinc ion, and two calcium ions. The catalytic zinc ion binds to three His residues in the HEXGHXXGXXH region in tetracoordination. The calcium ion binding play important role in stabilizing the secondary structure. MMP7 has
2610-416: Is linked to the catalytic domain by a flexible hinge region. The MMPs are initially synthesized as inactive zymogens with a pro-peptide domain that must be removed before the enzyme is active. The pro-peptide domain is part of the "cysteine switch." This contains a conserved cysteine residue that interacts with the zinc in the active site and prevents binding and cleavage of the substrate , keeping
2697-473: Is often derived from its substrate or the chemical reaction it catalyzes, with the word ending in -ase . Examples are lactase , alcohol dehydrogenase and DNA polymerase . Different enzymes that catalyze the same chemical reaction are called isozymes . The International Union of Biochemistry and Molecular Biology have developed a nomenclature for enzymes, the EC numbers (for "Enzyme Commission") . Each enzyme
MMP7 - Misplaced Pages Continue
2784-418: Is often referred to as "the lock and key" model. This early model explains enzyme specificity, but fails to explain the stabilization of the transition state that enzymes achieve. In 1958, Daniel Koshland suggested a modification to the lock and key model: since enzymes are rather flexible structures, the active site is continuously reshaped by interactions with the substrate as the substrate interacts with
2871-462: Is only one of several important kinetic parameters. The amount of substrate needed to achieve a given rate of reaction is also important. This is given by the Michaelis–Menten constant ( K m ), which is the substrate concentration required for an enzyme to reach one-half its maximum reaction rate; generally, each enzyme has a characteristic K M for a given substrate. Another useful constant
2958-560: Is regulated by the Wnt/ β catenin signaling pathway, and mediated by transformation growth factor β (TGF-β).TGF-β stimulates ECM and suppresses the steady-state level of MMP7, stromelysin mRNAs, and secretion of zymogens. The isoforms of TGF-β inhibit MMP7 mRNA and protein in the human endometrium via progesterone mediated pathway. However, the opposite effects of TGF-β on MMP7 were observed among transformed cells. In human glioma cell lines and human squamous cell carcinoma cell line II-4, TGF-β stimulates
3045-404: Is seen. This is shown in the saturation curve on the right. Saturation happens because, as substrate concentration increases, more and more of the free enzyme is converted into the substrate-bound ES complex. At the maximum reaction rate ( V max ) of the enzyme, all the enzyme active sites are bound to substrate, and the amount of ES complex is the same as the total amount of enzyme. V max
3132-403: Is the ribosome which is a complex of protein and catalytic RNA components. Enzymes must bind their substrates before they can catalyse any chemical reaction. Enzymes are usually very specific as to what substrates they bind and then the chemical reaction catalysed. Specificity is achieved by binding pockets with complementary shape, charge and hydrophilic / hydrophobic characteristics to
3219-588: Is thought to be involved in protein-protein interactions . This determines substrate specificity and is the site for interaction with TIMP's ( tissue inhibitor of metalloproteinases ). The hemopexin-like domain is absent in MMP-7 , MMP-23, MMP-26, and the plant and nematode . The membrane-bound MMPs (MT-MMPs) are anchored to the plasma membrane via a transmembrane or a GPI-anchoring domain. There are three catalytic mechanisms published. The MMPs can be subdivided in different ways. Use of bioinformatic methods to compare
3306-790: Is useful for comparing different enzymes against each other, or the same enzyme with different substrates. The theoretical maximum for the specificity constant is called the diffusion limit and is about 10 to 10 (M s ). At this point every collision of the enzyme with its substrate will result in catalysis, and the rate of product formation is not limited by the reaction rate but by the diffusion rate. Enzymes with this property are called catalytically perfect or kinetically perfect . Example of such enzymes are triose-phosphate isomerase , carbonic anhydrase , acetylcholinesterase , catalase , fumarase , β-lactamase , and superoxide dismutase . The turnover of such enzymes can reach several million reactions per second. But most enzymes are far from perfect:
3393-611: The DNA polymerases ; here the holoenzyme is the complete complex containing all the subunits needed for activity. Coenzymes are small organic molecules that can be loosely or tightly bound to an enzyme. Coenzymes transport chemical groups from one enzyme to another. Examples include NADH , NADPH and adenosine triphosphate (ATP). Some coenzymes, such as flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD), thiamine pyrophosphate (TPP), and tetrahydrofolate (THF), are derived from vitamins . These coenzymes cannot be synthesized by
3480-511: The law of mass action , which is derived from the assumptions of free diffusion and thermodynamically driven random collision. Many biochemical or cellular processes deviate significantly from these conditions, because of macromolecular crowding and constrained molecular movement. More recent, complex extensions of the model attempt to correct for these effects. Enzyme reaction rates can be decreased by various types of enzyme inhibitors. A competitive inhibitor and substrate cannot bind to
3567-465: The zinc -binding motif in the catalytic domain. The catalytic domain is connected to the C-terminal domain by a flexible hinge or linker region. This is up to 75 amino acids long, and has no determinable structure. The C-terminal domain has structural similarities to the serum protein hemopexin . It has a four-bladed β-propeller structure. β-Propeller structures provide a large flat surface that
MMP7 - Misplaced Pages Continue
3654-401: The C-terminal containing cysteine residues. Cysteine residues bind to the catalytic zinc keeping the protein latent. The dissociation of cysteine –Zinc coordination starts from the cleavage of the first 30 amino acids of the prodomain, which leads to a conformation change, and further results in autoproteolysis and the cleavage of the whole prodomain at Glu-Tyr site. According to Woessner et al.,
3741-548: The Mr of MMP7 is 28,000 for the latent form and 19,000 Mr for the active form after the cleavage of its prodomain. Promatrilysin (Pro-MMP7) is converted from the latent form to the active form by endoproteinases, and plasmin. Plasmin cleaves at the site recognizable to trypsin, is considered as the most possible physiological activator. In vitro, plasmin can activate pro-MMP7 to 50% of its full activity. Also, researchers used activated recombinant pro-MMP7 and purified substrates to investigate
3828-495: The PEA and AP-1 are required for Matrilysin/CAT reporter constructs induced by tumor promoter 12-O-tetradecanoulphorbol-13-acetate (TPA) and epidermal growth factor (EGF). In addition, the high level expression of AP-1 and its binding proteins were found to be associated with mutant Ki-Ras suggesting the high expression of matrilysin in Ras activated cells is AP-1 dependent. The expression of MMP7
3915-437: The active site and are involved in catalysis. For example, flavin and heme cofactors are often involved in redox reactions. Enzymes that require a cofactor but do not have one bound are called apoenzymes or apoproteins . An enzyme together with the cofactor(s) required for activity is called a holoenzyme (or haloenzyme). The term holoenzyme can also be applied to enzymes that contain multiple protein subunits, such as
4002-502: The active site. Organic cofactors can be either coenzymes , which are released from the enzyme's active site during the reaction, or prosthetic groups , which are tightly bound to an enzyme. Organic prosthetic groups can be covalently bound (e.g., biotin in enzymes such as pyruvate carboxylase ). An example of an enzyme that contains a cofactor is carbonic anhydrase , which uses a zinc cofactor bound as part of its active site. These tightly bound ions or molecules are usually found in
4089-751: The activity of the epithelial plasma membrane and associated substrates including E-cadherin, β4-integrin, TNF-alpha, RAS, heparin-binding EGF, IGF binding proteins and plasminogen. Further, this process promotes epithelial cell migration, proliferation and apoptosis. For menstruation, it promotes the endometrium regeneration after menstrual breakdown. Huang et al. reported that the proteolytic activity of MMP7 plays major role in tissue remodeling in biliary atresia-associated liver fibrosis. MMP7 cleaves collagen III/IV/V/IX/X/XI and proteoglycan indicating that MMP inhibitors can potentially be used in therapies that are involved in inhibition of tissue degradation, remodeling, anti-angiogenesis and inhibition of tumor invasion. MMP7
4176-407: The animal fatty acid synthase . Only a small portion of their structure (around 2–4 amino acids) is directly involved in catalysis: the catalytic site. This catalytic site is located next to one or more binding sites where residues orient the substrates. The catalytic site and binding site together compose the enzyme's active site . The remaining majority of the enzyme structure serves to maintain
4263-578: The average values of k c a t / K m {\displaystyle k_{\rm {cat}}/K_{\rm {m}}} and k c a t {\displaystyle k_{\rm {cat}}} are about 10 5 s − 1 M − 1 {\displaystyle 10^{5}{\rm {s}}^{-1}{\rm {M}}^{-1}} and 10 s − 1 {\displaystyle 10{\rm {s}}^{-1}} , respectively. Michaelis–Menten kinetics relies on
4350-502: The body de novo and closely related compounds (vitamins) must be acquired from the diet. The chemical groups carried include: Since coenzymes are chemically changed as a consequence of enzyme action, it is useful to consider coenzymes to be a special class of substrates, or second substrates, which are common to many different enzymes. For example, about 1000 enzymes are known to use the coenzyme NADH. Coenzymes are usually continuously regenerated and their concentrations maintained at
4437-500: The catalytic site inhibiting MMP7 activity. The activated MMP7 can also cleave the propeptides of proMMP2 and proMMP9 to facilitate tumor invasion. Quondamatteo et al. immunohistochemically stained MMP7, and localized MMP7 in early human liver development. They reported that MMP7 was presented in some hepatocytes and endothelial cells in the 6th gestational week, and only hematopoietic cells remained after that time. In order for MMPs to escape TIMP inhibition, active MMP7s are recruited to
SECTION 50
#17328850872074524-471: The chemical equilibrium of the reaction. In the presence of an enzyme, the reaction runs in the same direction as it would without the enzyme, just more quickly. For example, carbonic anhydrase catalyzes its reaction in either direction depending on the concentration of its reactants: The rate of a reaction is dependent on the activation energy needed to form the transition state which then decays into products. Enzymes increase reaction rates by lowering
4611-425: The conversion of starch to sugars by plant extracts and saliva were known but the mechanisms by which these occurred had not been identified. French chemist Anselme Payen was the first to discover an enzyme, diastase , in 1833. A few decades later, when studying the fermentation of sugar to alcohol by yeast , Louis Pasteur concluded that this fermentation was caused by a vital force contained within
4698-433: The energy of the transition state. First, binding forms a low energy enzyme-substrate complex (ES). Second, the enzyme stabilises the transition state such that it requires less energy to achieve compared to the uncatalyzed reaction (ES ). Finally the enzyme-product complex (EP) dissociates to release the products. Enzymes can couple two or more reactions, so that a thermodynamically favorable reaction can be used to "drive"
4785-587: The enzyme urease was a pure protein and crystallized it; he did likewise for the enzyme catalase in 1937. The conclusion that pure proteins can be enzymes was definitively demonstrated by John Howard Northrop and Wendell Meredith Stanley , who worked on the digestive enzymes pepsin (1930), trypsin and chymotrypsin . These three scientists were awarded the 1946 Nobel Prize in Chemistry. The discovery that enzymes could be crystallized eventually allowed their structures to be solved by x-ray crystallography . This
4872-483: The enzyme at the same time. Often competitive inhibitors strongly resemble the real substrate of the enzyme. For example, the drug methotrexate is a competitive inhibitor of the enzyme dihydrofolate reductase , which catalyzes the reduction of dihydrofolate to tetrahydrofolate. The similarity between the structures of dihydrofolate and this drug are shown in the accompanying figure. This type of inhibition can be overcome with high substrate concentration. In some cases,
4959-475: The enzyme in an inactive form. In the majority of the MMPs, the cysteine residue is in the conserved sequence PRCGxPD. Some MMPs have a prohormone convertase cleavage site (Furin-like) as part of this domain, which, when cleaved, activates the enzyme. MMP-23A and MMP-23B include a transmembrane segment in this domain. X-ray crystallographic structures of several MMP catalytic domains have shown that this domain
5046-403: The enzyme. As a result, the substrate does not simply bind to a rigid active site; the amino acid side-chains that make up the active site are molded into the precise positions that enable the enzyme to perform its catalytic function. In some cases, such as glycosidases , the substrate molecule also changes shape slightly as it enters the active site. The active site continues to change until
5133-427: The enzyme. For example, the enzyme can be soluble and upon activation bind to a lipid in the plasma membrane and then act upon molecules in the plasma membrane. Allosteric sites are pockets on the enzyme, distinct from the active site, that bind to molecules in the cellular environment. These molecules then cause a change in the conformation or dynamics of the enzyme that is transduced to the active site and thus affects
5220-676: The expression of MMP7 mRNA and proteins, and facilities the invasive behavior of cells. The promoter region of the human MMP7 gene contains two or more sites that are homologous to the NR-IL6 binding sequences indicating MMP7 can bind to IL-1 and IL-6. In addition, the level of MMP7 mRNA is elevated followed the treatment of tumor necrosis factor α (TNF- α) and IL-1 β in human mesangial cells. MMP7 are commonly expressed in epithelial cells including ductal epithelium of exocrine glands in skin, salivary glands, pancreas, glandular epithelium of intestine and reproductive organ, liver, and breast. In addition, MMP7
5307-535: The growth. Enzyme Enzymes ( / ˈ ɛ n z aɪ m z / ) are proteins that act as biological catalysts by accelerating chemical reactions . The molecules upon which enzymes may act are called substrates , and the enzyme converts the substrates into different molecules known as products . Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes
SECTION 60
#17328850872075394-476: The inhibitor can bind to a site other than the binding-site of the usual substrate and exert an allosteric effect to change the shape of the usual binding-site. Matrix metalloproteinase Matrix metalloproteinases ( MMPs ), also known as matrix metallopeptidases or matrixins , are metalloproteinases that are calcium -dependent zinc -containing endopeptidases ; other family members are adamalysins , serralysins , and astacins . The MMPs belong to
5481-609: The latent progelatinase A to its active form. Proteins of the matrix metalloproteinase (MMP) family are involved in the breakdown of extracellular matrix in normal physiological processes, such as embryonic development , reproduction , and tissue remodeling, as well as in disease processes, such as arthritis and metastasis . Most MMP's are secreted as inactive proproteins which are activated when cleaved by extracellular proteinases . The enzyme encoded by this gene degrades proteoglycans , fibronectin , elastin and casein and differs from most MMP family members in that it lacks
5568-493: The metal binding protein, metallothionine; thus helping in metal binding mechanism. The MMPs play an important role in tissue remodeling associated with various physiological or pathological processes such as morphogenesis , angiogenesis , tissue repair , cirrhosis , arthritis , and metastasis . MMP-2 and MMP-9 are thought to be important in metastasis. MMP-1 is thought to be important in rheumatoid arthritis and osteoarthritis. Recent data suggests active role of MMPs in
5655-468: The mixture. He named the enzyme that brought about the fermentation of sucrose " zymase ". In 1907, he received the Nobel Prize in Chemistry for "his discovery of cell-free fermentation". Following Buchner's example, enzymes are usually named according to the reaction they carry out: the suffix -ase is combined with the name of the substrate (e.g., lactase is the enzyme that cleaves lactose ) or to
5742-430: The opposite side of the catalytic site of MMP7 are required for cholesterol sulfate binding. Wild type MMP7 can digest fibronectin, but mutant MMP7 fails to induce the aggregation of colon cancer cells. In addition, Qasim et al. reported that MMP7 is highly expressed in advanced colorectal adenomatous polys with severe dysplasia. Further, MMP7 is involved in converting colorectal adenomas into malignant state and facilitating
5829-584: The pathogenesis of Aortic Aneurysm. Excess MMPs degrade the structural proteins of the aortic wall. Disregulation of the balance between MMPs and TIMPs is also a characteristic of acute and chronic cardiovascular diseases. All MMPs are synthesized in the latent form (Zymogen). They are secreted as proenzymes and require extracellular activation. They can be activated in vitro by many mechanisms including organomercurials, chaotropic agents, and other proteases. The MMPs are inhibited by specific endogenous tissue inhibitor of metalloproteinases (TIMPs), which comprise
5916-420: The plasma membrane of epithelium inducing membrane-associated growth factors processing for epithelial repair and proliferation. In human endometrium, the expression of MMP7 mRNA increases at menstruation and remains high during the proliferative phase. Also, MMP-7 binds to the plasma membrane of epithelium containing cholesterol-rich domain. The bounded MMP7 is active and resistant to TIMP inhibition. It promotes
6003-528: The precise orientation and dynamics of the active site. In some enzymes, no amino acids are directly involved in catalysis; instead, the enzyme contains sites to bind and orient catalytic cofactors . Enzyme structures may also contain allosteric sites where the binding of a small molecule causes a conformational change that increases or decreases activity. A small number of RNA -based biological catalysts called ribozymes exist, which again can act alone or in complex with proteins. The most common of these
6090-478: The primary sequences of the MMPs suggest the following evolutionary groupings of the MMPs: Analysis of the catalytic domains in isolation suggests that the catalytic domains evolved further once the major groups had differentiated, as is also indicated by the substrate specificities of the enzymes . The most commonly used groupings (by researchers in MMP biology) are based partly on historical assessment of
6177-421: The proteolytic activity of MMp7 in vitro, and found that MMP7 cleaves many protein substrates mainly including ECM components, proMMPs, and nonmatrix proteins. MMP7 cleaves the glycoprotein entactin that links laminin and collagen IV at about 100-600 times faster than collagenase-1. In addition, MMP7 can activate other MMPs. Activated MMP7 and APMA can increase the activity of collagenase-1, and MMP7 can also convert
6264-493: The proteolytic process of the precursors of tumor necrosis factors and urokinase plasminogen activators. MMP7 cleaves cell surface proteins, promotes adhesion of cancer cells, and increases the potential of tumor metastasis. Higashi et al. reported that the binding of MMP7 to cholesterol sulfate on the cell surface plays a critical role in the cell membrane-related proteolytic action. Also, the internal Ile 29, Arg33, Arg51, and Trp 55 and 171-173 residues at MMP7 C-terminal located on
6351-406: The reaction and releases the product. This work was further developed by G. E. Briggs and J. B. S. Haldane , who derived kinetic equations that are still widely used today. Enzyme rates depend on solution conditions and substrate concentration . To find the maximum speed of an enzymatic reaction, the substrate concentration is increased until a constant rate of product formation
6438-733: The reaction rate of the enzyme. In this way, allosteric interactions can either inhibit or activate enzymes. Allosteric interactions with metabolites upstream or downstream in an enzyme's metabolic pathway cause feedback regulation, altering the activity of the enzyme according to the flux through the rest of the pathway. Some enzymes do not need additional components to show full activity. Others require non-protein molecules called cofactors to be bound for activity. Cofactors can be either inorganic (e.g., metal ions and iron–sulfur clusters ) or organic compounds (e.g., flavin and heme ). These cofactors serve many purposes; for instance, metal ions can help in stabilizing nucleophilic species within
6525-410: The same enzymatic activity have been called non-homologous isofunctional enzymes . Horizontal gene transfer may spread these genes to unrelated species, especially bacteria where they can replace endogenous genes of the same function, leading to hon-homologous gene displacement. Enzymes are generally globular proteins , acting alone or in larger complexes . The sequence of the amino acids specifies
6612-412: The structure which in turn determines the catalytic activity of the enzyme. Although structure determines function, a novel enzymatic activity cannot yet be predicted from structure alone. Enzyme structures unfold ( denature ) when heated or exposed to chemical denaturants and this disruption to the structure typically causes a loss of activity. Enzyme denaturation is normally linked to temperatures above
6699-519: The substrate is completely bound, at which point the final shape and charge distribution is determined. Induced fit may enhance the fidelity of molecular recognition in the presence of competition and noise via the conformational proofreading mechanism. Enzymes can accelerate reactions in several ways, all of which lower the activation energy (ΔG , Gibbs free energy ) Enzymes may use several of these mechanisms simultaneously. For example, proteases such as trypsin perform covalent catalysis using
6786-412: The substrate specificity of the MMP and partly on the cellular localization of the MMP. These groups are the collagenases, the gelatinases, the stromelysins, and the membrane-type MMPs (MT-MMPs). However, it is becoming increasingly clear that these divisions are somewhat artificial as there are a number of MMPs that do not fit into any of the traditional groups. Matrix metalloproteinases combines with
6873-405: The substrates. Enzymes can therefore distinguish between very similar substrate molecules to be chemoselective , regioselective and stereospecific . Some of the enzymes showing the highest specificity and accuracy are involved in the copying and expression of the genome . Some of these enzymes have " proof-reading " mechanisms. Here, an enzyme such as DNA polymerase catalyzes a reaction in
6960-399: The synthesis of antibiotics . Some household products use enzymes to speed up chemical reactions: enzymes in biological washing powders break down protein, starch or fat stains on clothes, and enzymes in meat tenderizer break down proteins into smaller molecules, making the meat easier to chew. By the late 17th and early 18th centuries, the digestion of meat by stomach secretions and
7047-483: The treatment of periodontal disease and is the only MMP inhibitor that is widely available clinically. It is sold under the trade name Periostat by the company CollaGenex . Minocycline, another tetracycline antibiotic, has also been shown to inhibit MMP activity. A number of rationally designed MMP inhibitors have shown some promise in the treatment of pathologies that MMPs are suspected to be involved in (see above). However, most of these, such as marimastat (BB-2516),
7134-438: The type of reaction (e.g., DNA polymerase forms DNA polymers). The biochemical identity of enzymes was still unknown in the early 1900s. Many scientists observed that enzymatic activity was associated with proteins, but others (such as Nobel laureate Richard Willstätter ) argued that proteins were merely carriers for the true enzymes and that proteins per se were incapable of catalysis. In 1926, James B. Sumner showed that
7221-486: The yeast cells called "ferments", which were thought to function only within living organisms. He wrote that "alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells." In 1877, German physiologist Wilhelm Kühne (1837–1900) first used the term enzyme , which comes from Ancient Greek ἔνζυμον (énzymon) ' leavened , in yeast', to describe this process. The word enzyme
7308-413: The zinc atom. Other substituents of these inhibitors are usually designed to interact with various binding pockets on the MMP of interest, making the inhibitor more or less specific for given MMPs. Doxycycline , at subantimicrobial doses, inhibits MMP activity, and has been used in various experimental systems for this purpose, such as for recalcitrant recurrent corneal erosions. It is used clinically for
7395-581: Was first done for lysozyme , an enzyme found in tears, saliva and egg whites that digests the coating of some bacteria; the structure was solved by a group led by David Chilton Phillips and published in 1965. This high-resolution structure of lysozyme marked the beginning of the field of structural biology and the effort to understand how enzymes work at an atomic level of detail. Enzymes can be classified by two main criteria: either amino acid sequence similarity (and thus evolutionary relationship) or enzymatic activity. Enzyme activity . An enzyme's name
7482-622: Was isolated in 1988 by Muller et al. MMP7 is a member of the matrix metalloproteinase (MMP) family consisting of structural-related zinc-dependent endopeptidases . The primary role of cleaved/activated MMP7 is to break down extracellular matrix by degrading macromolecules including casein, type I, II, IV, and V gelatins , fibronectin , and proteoglycan . The human MMP7 is located on chromosome 11 q22.3. MMP genes are clustered in q region of human Chromosome 11 including matrilysin, collagenase-1, stromelysin1, stromelysin-2, and metalloelastase genes. It consists of 267 amino acids. The cDNA of MMP7
7569-451: Was used later to refer to nonliving substances such as pepsin , and the word ferment was used to refer to chemical activity produced by living organisms. Eduard Buchner submitted his first paper on the study of yeast extracts in 1897. In a series of experiments at the University of Berlin , he found that sugar was fermented by yeast extracts even when there were no living yeast cells in
#206793