Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.23 (MMP)
 4,246 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

ACTIVE LI EFFLUX FROM HUMAN ERYTHROCYTES WAS SHOWN TO BE MEDIATED BY THE NA/K PUMP: (i) intracellular Li (Li(c)) activated ouabain-sensitive K influx, and (ii) a portion of the Li efflux required external K and was inhibited by ouabain. In activating K influx, Li(c) interacts with the pump like Na rather than like K-depleting the cells of orthophosphate inhibited activation of K influx by intracellular K (K/K exchange) but did not inhibit Li-activated K influx. (To show these interactions of Li(c) with the Na/K pump, p-chloromercuribenzenesulfonate or nystatin was used to allow replacement of intracellular Na and K with Li and choline.) From kinetic studies of the pump, it was shown that the apparent affinity of the intracellular aspect of the Na/K pump for Li was an order of magnitude less than that for Na. From simultaneous measurements of ouabain-sensitive net fluxes of Li and K in Na-free cells, it was shown that the pump-mediated K influx and Li efflux were coupled. The stoichiometry of the coupling ratio was close to 1:1 for Li:K, different from the coupling ratio of 3:2 for Na:K in the pump's normal mode of operation. It had been shown previously that the Na/K pump in human erythrocytes mediates active Li influx. Because it also mediates active Li efflux, the molecular mechanisms for distinguishing between Na and K must be qualitatively different at the internal and external aspects of the pump. The possible relevance of the results of this study to manic depressive illness and Li therapy is discussed.
 ...
PMID:Lithium efflux through the Na/K pump in human erythrocytes. 26 58

The action of three matrix metalloproteinases (MMPs), 72- and 95-kDa gelatinases (MMP-2 and MMP-9) and PUMP (MMP-7), and a cysteine proteinase, cathepsin B, were investigated on aggrecan the major proteoglycan of cartilage. All the enzymes cleaved aggrecan although the activity of the 95-kDa gelatinase was very low. Specific cleavage sites were investigated following incubation with a purified aggrecan G1-G2 domain fragment (150 kDa). Both gelatinases produced 110-kDa G2 and 56-kDa G1 products by a single cleavage at an Asn-Phe bond within the interglobular domain close to the G1 domain. This was similar to the action of stromelysin (MMP-3) (Fosang, A. J., Neame, P. J., Hardingham, T. E., Murphy, G., and Hamilton, J. A. (1991) J. Biol. Chem. 266, 15579-15582). Cathepsin B also produced two fragments from a single cleavage at a Gly-Val bond only three amino acids C-terminal to the metalloproteinase cleavage site. PUMP cleaved at the metalloproteinase Asn-Phe site, but in addition produced a low yield of a smaller G2 fragment (56 kDa) corresponding to cleavage between Asp441 and Leu442 (human sequence), within the interglobular domain, close to the G2 domain. The apparent difference in size between the two G2 fragments released by PUMP (110 and 56 kDa) was much greater than predicted from the peptide length between the cleavage sites (100 amino acids). However, keratanase digestion greatly reduced the size of the 110-kDa G2 fragment, while producing only a small reduction in size of the 56-kDa product, showing that there was approximately 30-40 kDa of keratan sulfate attached to the interglobular domain between the PUMP cleavage sites. This new structural information on aggrecan may account for the previously observed stiffness of the interglobular domains when viewed by rotary shadowing electron microscopy (Paulsson, M., Morgelin, M., Wiedemann, H., Beardmore-Gray, M., Dunham, D. G., Hardingham, T. E., Heinegard, D., Timpl, R., and Engel, J. (1987) Biochem. J. 245, 763-772). These results show that in spite of a high keratan sulfate content the interglobular domain provides important sites for cleavage by different proteinases, including several members of the matrix metalloproteinase family.
 ...
PMID:The interglobular domain of cartilage aggrecan is cleaved by PUMP, gelatinases, and cathepsin B. 132 52

Matrilysin (PUMP, MMP-7) is a member of the metalloprotease gene family, whose constituents are responsible for the remodeling of extracellular matrix. The matrilysin protein is a 28-kDa zymogen possessing catalytic activities against a broad range of extracellular matrix substrates including proteoglycans, gelatin, fibronectin, laminin, and elastin. To gain insights into the biological expression of matrilysin in human cell types, we generated a monospecific, polyclonal antibody against a 16-amino acid sequence derived from its catalytic domain, a region which lacked significant homology with other matrix metalloenzymes. We found this antibody capable of precipitating a 28-kDa protein from the conditioned media of human bone marrow-derived promonocytes and human peripheral blood monocytes cultivated in vitro. Promonocyte matrilysin was rapidly converted to a 19-kDa form by organomercurial activation. While matrilysin was constitutively synthesized by bone marrow-derived promonocytes, its secretion was markedly up-regulated by the mononuclear phagocyte activator, lipopolysaccharide. Furthermore, despite its expression in monocyte precursors, blood monocytes, and monocyte-derived macrophages, matrilysin was not synthesized by human alveolar macrophages under any tested condition. In situ hybridization studies with matrilysin cRNA confirmed the presence of specific mRNA in both human promonocytes and monocytes. Moreover, a marked increase in hybridizable mRNA was observed with lipopolysaccharide treatment suggesting that matrilysin synthesis is pretranslationally regulated. In summary, this represents the first report documenting constitutive and regulated synthesis of matrilysin by a normal human cell type and suggests that matrilysin is expressed as a significant secreted product of mononuclear phagocytes at an intermediate stage of cellular differentiation.
 ...
PMID:The matrix metalloprotease matrilysin (PUMP) is expressed in developing human mononuclear phagocytes. 137 84

The latent precursor of matrilysin (EC 3.4.24.23; punctuated metalloproteinase (PUMP) was purified from transfected mouse myeloma cell conditioned medium and was found to contain one zinc atom per molecule which was essential for catalytic activity. Promatrilysin could be activated to the same specific activity by (4-aminophenyl)mercuric acetate, trypsin, and incubation at elevated temperatures (heat activation). Active matrilysin hydrolyzed the fluorescent substrate 2,4-dinitrophenyl-Pro-Leu-Gly-Leu-Trp-Ala-D-Arg-NH2 at the Gly-Leu bond with a maximum value for kcat/Km of 1.3 x 10(4) M-1 s-1 at the pH optimum of 6.5 and pKa values of 4.60 and 8.65. Activity is inhibited by the tissue inhibitor of metalloproteinases-1 in a 1:1 stoichiometric interaction. Analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis in conjunction with N-terminal sequencing revealed that, as with all other matrix metalloproteinases similarly studied, promatrilysin activation was accompanied by the stepwise proteolytic removal of an M(r) 9000 propeptide from the N-terminus. The intermediates generated were dependent on the mode of activation used but, in all cases studied, activation terminated with an autocatalytic cleavage at E77-Y78 to yield the final M(r) 19,000 active matrilysin. From an analysis of the stability of the various intermediates, we propose that the sequence L13-K33 is particularly important in protecting the E77-Y78 site from autocatalytic cleavage, thereby maintaining the latency of the proenzyme.
 ...
PMID:Biochemical characterization of matrilysin. Activation conforms to the stepwise mechanisms proposed for other matrix metalloproteinases. 139 Jun 35

The tissue inhibitor of metalloproteinases-1 (TIMP-1) was subjected to single-site mutations within the N-terminal three loops using an oligonucleotide-directed polymerase chain reaction method. All the histidines, and a number of other residues conserved between TIMP-1 and TIMP-2, were individually modified and the mutant TIMPs expressed in mammalian cells. Purified mutant TIMPs were shown to be correctly folded by measuring the effect of guanidine hydrochloride on intrinsic fluorescence. Kinetic analyses of mutants using a quenched fluorescent peptide substrate and the metalloproteinase PUMP indicated that mutation of His7 and Gln9 caused an increase in the apparent dissociation constant, largely due to an increase in the rate of dissociation of complexes. The data indicate that the anchored sequence between Cys 3 and Cys 13 is a key region for interaction of TIMP-1 with metalloproteinases.
 ...
PMID:Site-directed mutations that alter the inhibitory activity of the tissue inhibitor of metalloproteinases-1: importance of the N-terminal region between cysteine 3 and cysteine 13. 142 Jan 37

(7-methoxycoumarin-4-yl)Acetyl-Pro-Leu-Gly-Leu-(3-[2,4-dinitrophenyl]-L- 2,3-diaminopropionyl)-Ala-Arg-NH2 (Mca-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH2) has been synthesised as a fluorogenic substrate for the matrix metalloproteinases. The highly fluorescent 7-methoxycoumarin group is efficiently quenched by energy transfer to the 2,4-dinitrophenyl group. The punctuated metalloproteinase (PUMP, EC 3.4.24.23) cleaves the substrate at the Gly-Leu bond with a 190-fold increase in fluorescence (lambda cx 328 nm, lambda cm 393 nm). In assays of the human matrix metalloproteinases. Mca-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH2 is about 50 to 100 times more sensitive than dinitrophenyl-Pro-Leu-Gly-Leu-Trp-Ala-D-Arg-NH2 and continuous assays can be made at enzyme concentrations comparable to those used with macromolecular substrates. Specificity constants (kcat/Km) are reported for both synthetic substrates with PUMP, collagenase, stromelysin and 72 kDa gelatinase.
 ...
PMID:A novel coumarin-labelled peptide for sensitive continuous assays of the matrix metalloproteinases. 153

Nuclear matrins are proteins that localize to the internal nuclear matrix. In a previous study, we reported that histone deacetylase is a component of the internal matrix, suggesting that histone deacetylase is a nuclear matrin. Here, we demonstrate that the majority of the histone deacetylase activity is associated with the internal nuclear matrices of chicken and trout liver. Thus, the association of the histone deacetylase with the internal nuclear matrix is neither tissue- nor species-specific. Using histone deacetylase as a marker enzyme for the partitioning of the internal nuclear matrix during nuclear fractionations, we show that in contrast to the internal nuclear matrices of trout liver, trout hepatocellular carcinoma and chicken liver, the stability of the chicken erythrocyte internal nuclear matrix is temperature-dependent. Our results support a model that has the histone deacetylase mediating transient interactions between the internal nuclear matrix and chromatin regions undergoing dynamic acetylation, for example transcriptionally active chromatin regions.
 ...
PMID:Nuclear distribution of histone deacetylase: a marker enzyme for the internal nuclear matrix. 156 6

The enzyme responsible for the metalloproteinase activity which cleaves the Glu143-Leu144 bond of (pro)urokinase has been isolated from the conditioned medium of cultured normal human kidney cells. Using S-Sepharose and Cibacron Blue-agarose chromatography, then C-4 reversed phase high pressure liquid chromatography, a protein of about 20,000 Da was isolated. Through an identical amino-terminal sequence, the protein was shown to be the matrix metalloproteinase previously referred to in the literature as "pump-1" (putative metalloproteinase). When aprotinin was added during the course of the purification, the major species isolated was the zymogen form (28,000 Da) of pump-1. Pump-1 has been shown to efficiently cleave the susceptible bond of both pro-urokinase (single-chain) and active (two-chain) urokinase and thereby produce the corresponding low molecular weight forms. The amino-terminal sequences of the A and B chains of low molecular weight urokinase prepared by action of pump-1 on recombinant high molecular weight urokinase are identical to those of the low molecular weight urokinase isolated from human kidney cell culture. Since the reaction of urokinase with this metalloproteinase results in separation of its serine proteinase region from the domain which mediates binding to the urokinase receptor, it may be of importance in the regulation of the functional activity of the plasminogen activator in cellular processes.
 ...
PMID:The matrix metalloproteinase pump-1 catalyzes formation of low molecular weight (pro)urokinase in cultures of normal human kidney cells. 162 80

The gene for PUMP (putative metalloproteinase), a human matrix metalloproteinase, was synthesized by a PCR-based method. The DNA fragment of 546 bases containing the PUMP gene was generated by overlap extension of six long oligonucleotides (length ranging from 101 to 116 bases) and subsequent amplification by two short terminal oligonucleotide primers (length from 20 to 48 bases) in one pot without using restriction and ligation enzymes. The synthetic gene was cloned into a T7 expression vector in two ways to express PUMP as a non-fusion protein. Both constructs showed high level expression in E. coli.
 ...
PMID:Gene synthesis and expression in E. coli for pump, a human matrix metalloproteinase. 163 63

Metalloproteinase inhibitors were surveyed with the culture media of 19 kinds of human tumor cell lines, using transin (rat stromelysin) as the target enzyme. This survey showed that most of the cell lines more or less secreted inhibitor activity, and that a human hepatoma cell line, HLE, secreted an extremely high inhibitor activity into the culture medium. Two kinds of metalloproteinase inhibitors were purified from the serum-free conditioned medium of HLE cells. The major inhibitor, which showed a single protein band with a molecular weight (Mr) of 21,000 (21k) (nonreduced) or 24k (reduced) on SDS-polyacrylamide gel electrophoresis, was identified as TIMP-2 (tissue inhibitor of metalloproteinases-2) by the analysis of its N-terminal amino acid sequence. The other was immunologically identified as TIMP. Purified TIMP-2 inhibited the activities of transin, matrin (pump-1), Mr 72k gelatinase, and interstitial collagenase with 1:1 stoichiometry. When the latent precursor form (Mr 57k) of transin was incubated with p-aminophenylmercuric acetate as an activating reagent, TIMP-2 inhibited the conversion of the intermediate form (Mr 45k) into the mature enzyme (Mr 42k). This indicated that TIMP-2 regulates not only the activity of the mature enzyme but also the autolytic processing of the proenzyme. TIMP-2 also inhibited in vitro tumor invasion through reconstituted basement membrane (matrigel) in chemotaxis chambers, showing that the metalloproteinase inhibitors as well as the extracellular matrix metalloproteinases are involved in tumor invasion through basement membrane and other extracellular matrices.
 ...
PMID:Efficient purification of TIMP-2 from culture medium conditioned by human hepatoma cell line, and its inhibitory effects on metalloproteinases and in vitro tumor invasion. 166 1


1 2 3 4 5 6 7 8 9 10 Next >>