Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.7 (plasmin)
9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The insulin-like growth factors, IGF-I and IGF-II, are proteins that promote cellular growth and differentiation of various organs, including the kidney. These peptides interact with high affinity cell surface receptors and bind to a family of IGF-binding proteins (IGFBPs). Altered serum and urinary IGFBP patterns in children with chronic renal failure have been previously described. In this study, we evaluated serum and urinary IGFBP profiles in acute renal failure patients (ARF; n = 10) and chronic renal failure patients (n = 10), using Western ligand blots. Most patients with acute or chronic renal failure showed decreased intact serum IGFBP-3 and increased serum IGFBP-2. Both groups displayed marked urinary IGFBP alterations, including increased urinary IGFBP-1 and totally absent urinary IGFBP-3, as detected by Western ligand blot. To evaluate altered IGFBP profiles, we performed IGFBP-3 protease assays with sera and urine from renal failure patients and normal controls. Although control urine had only minor protease activity (defined by the ability to degrade [125I]IGFBP-3), significant protease activity was found in urine from renal failure patients. The proteolytic pattern and susceptibility to protease inhibitors in most renal failure urine samples were the same as those seen in normal urine and with plasmin. Protease activity was completely inhibited by serine protease inhibitors. We speculate that urinary protease activity is mediated primarily by a serine protease(s), which may be involved in the modulation of renal IGF activity in health and disease.
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PMID:Alteration in insulin-like growth factor-binding proteins (IGFBPs) and IGFBP-3 protease activity in serum and urine from acute and chronic renal failure. 752 35

The adhesive glycoprotein vitronectin (VN) shows a high degree of conformational flexibility implicating that different molecular forms of the molecular may exist. Conformation-dependent monoclonal antibodies 13H1 or 16A7 that, per se, did not react with plasma VN bound to VN treated with heparin, chaotropes, detergents, pH below 6, or by heating at 56 degrees C. Dependent on the stimulus, recognition of VN by these antibodies varied and preceded heparin binding and self-association of VN resulting in the formation of noncovalently linked multimeric species of the protein. Both monoclonal antibodies also reacted with VN in serum or in platelet releasates as well as with VN in extracellular matrices of endothelial cells and inhibited cell adhesion on immobilized VN. Critical VN levels were needed for concentration-dependent multimerization indicating a nonlinear type of polymerization process. The nature of VN multimers was judged by nondenaturing gel electrophoresis, gel filtration, and sucrose gradient ultracentrifugation and revealed the formation of 3- to 16-mer multimeric species within an M(r) range of 200-1200 kDa representing a mean sedimentation coefficient of 9.6 S. In electron microscopy, multimeric VN occurred as globular specimens with an average diameter of 15-28 nm (monomeric plasma VN, 6-8 nm). In contrast to plasma VN, VN multimers were efficiently stabilized by covalent inter-molecular bonds following chemical or transglutaminase-induced cross-linking. A synthetic peptide comprising the central heparin binding region of VN (residues 348-361) not only bound to plasma VN but induced its multimerization also in plasma. During plasmin proteolysis of VN, fragments were generated that lacked the heparin binding region and that lost the ability to multimerize following urea or detergent treatment, implicating that the highly basic region is essential for multimer formation. These data suggest that non-plasma forms of VN, which are abundant in platelets and subendothelium, represent the prototype conformer of the reactive heparin binding form of VN. Our findings implicate that conformationally altered forms of VN enable the adhesive protein to multimerize in a characteristic fashion and thereby endow extracellular matrix sites with unique multivalent properties.
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PMID:Multimeric vitronectin. Identification and characterization of conformation-dependent self-association of the adhesive protein. 769 80

We have created a novel thrombolytic agent by the combination of mutation with partial deletion of tissue-type plasminogen activator (t-PA). We constructed Escherichia coli expression vectors for (i) native t-PA (nt-PA) and its derivatives; (ii) K1K2P, consisting of kringle 1 (K1), kringle 2 (K2), and protease (P) domains; (iii) K2P, consisting of K2 and P domains; (iv) D-nt-PA; (v) D-K1K2P; and (vi) D-K2P. The latter three are point mutants of nt-PA, K1K2P, and K2P, respectively, in which Arg275 (number corresponds to that of nt-PA) has been mutated to Asp. The production of nt-PA and its derivatives was remarkably improved by (i) removal of the 3' noncoding region of nt-PA cDNA from expression vectors and (ii) expression in mutant E. coli derived from E. coli HB101, which is insensitive to heat-shock inductions. The proteins produced were precipitated as insoluble aggregates in the cells and were renatured to active forms by extraction with 8 M urea followed by dialysis against a redox buffer containing GSH and GSSG. The renaturation yield depended on the pH of the buffer and the number of disulfide bonds of the proteins (nt-PA << K1K2P < K2P). The mutation of Arg275 (the plasmin cleavage site) caused an increase in the catalytic enhancement by fibrin and a decrease of the interaction with plasminogen activator inhibitors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Production and characterization of a novel tissue-type plasminogen activator derivative in Escherichia coli. 776 73

The major proteins in milks from bovine, caprine, porcine, and murine animals and from humans were compared using a two-dimensional analysis method. In the first dimension, proteins were separated by their isoelectric points using preparative isoelectric focusing in pH gradient of 3 to 10. Twenty fractions from each sample were then analyzed by urea-PAGE and SDS-PAGE. Two-dimensional gels showed characteristic patterns for each milk. Major bovine milk proteins were identified and used as reference for proteins of other mammals. Additionally, some peptides resulting from plasmin hydrolysis were characterized. Caprine milk proteins showed a pattern similar to that of bovine milk except for the absence of alpha s1-caseins. alpha-Lactalbumin of bovine and caprine milks resolved as two bands in an immunoblot using bovine alpha-lactalbumin antibody. Each band corresponded to normal and glycosylated alpha-lactalbumin. Human, porcine, and murine milk proteins were totally different from those of ruminant milks on the two-dimensional gels. Two-dimensional analysis using preparative isoelectric focusing, followed by PAGE, was a useful method to compare major milk proteins in several mammals because of the rapid simultaneous separation into 20 fractions. This fractionation allows additional analytical procedures for more efficient comparison of chemical and physical properties of the proteins.
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PMID:Comparison of milk proteins using preparative isoelectric focusing followed by polyacrylamide gel electrophoresis. 796 43

The experiments reported here were carried out to define in greater detail actin's stimulation of plasmin generation by t-PA. Actin did not alter t-PA's hydrolysis of a synthetic substrate, and thus is unlikely to have a direct effect upon t-PA's proteolytic activity. When studied in a single-stage assay, actin accelerated t-PA-mediated plasmin generation from both Glu-plasminogen and Lys-plasminogen, indicating the central role of ternary complex formation. Although actin does not appear to bind two-chain urokinase (tcu-PA), it stimulates tcu-PA's cleavage of Glu-plasminogen. This finding suggests that actin alters the conformation of Glu-plasminogen to an open form. The failure of actin to increased plasmin generation by tcu-PA acting on Lys-plasminogen, which is in an open configuration, is consistent with this interpretation. Immunoglobin G, which shares with actin the property of binding to Glu-plasminogen after nicking by plasmin, did not stimulate tcu-PA's cleavage of Glu-plasminogen, indicating the uniqueness of actin's effects and suggesting interactions between actin and plasminogen at multiple binding sites. Unlike fibrin and heparin, whose stimulation of t-PA is related to polymer length actin is able to stimulate t-PA when presented in either a monomeric or polymeric form. Denaturation of actin by exposure to urea and guanidine increased its ability to stimulate plasmin generation by t-PA. Because actin's structure is maintained by a noncovalently bound adenine nucleotide (ATP or ADP), exposure to ATP/ADPases found in plasma and on cell membranes might also result in its denaturation. Actin treated with an enzyme functionally similar to such ecto-ATP/ADPases, potato apyrase, was more potent than native actin in stimulating plasmin generation by t-PA. The effects of apyrase were blocked by the addition of the plasma actin-binding proteins, gelsolin and the vitamin D-binding protein (DBP). Thus, denaturation of actin may occur in under physiologic conditions, with potential biological consequences. Actin thus appears to be unique with regard to its interactions with the fibrinolytic system and plasma actin-binding proteins may serve to protect the host from the effects of denatured actin.
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PMID:Actin stimulates plasmin generation by tissue and urokinase-type plasminogen activators. 823 51

Denaturation of rabbit skeletal-muscle AMP deaminase in acidic medium followed by chromatography on DEAE-cellulose in 8 M urea atpH 8.0 allows separation of two main peptide components of similar apparent molecular mass (75-80 kDa) that we tentatively assume correspond to two different enzyme subunits. Whereas the amino acid composition of one of the two peptides is in good agreement with that derived from the nucleotide sequence of the known rat and human AMPD1 cDNAs, the second component shows much higher contents of proline, glycine and histidine. N-Terminal sequence analysis of the fragments liberated by limited proteolysis with trypsin of the novel peptide reveals a striking similarity to the fragments produced by plasmin cleavage of the rabbit plasma protein called histidine-proline-rich glycoprotein (HPRG). However, some divergence is observed between the sequence of one of the fragments liberated from AMP deaminase by a more extensive trypsinization and rabbit plasma HPRG in the region containing residues 472-477. A fragment with a blocked N-terminus, which was found among those liberated by proteolysis with pepsin of either whole AMP deaminase or the novel component of the enzyme, shows an amino acid composition quite different from that of the N-terminus of the known subunit of AMP deaminase. By coupling this observation with the detection in freshly prepared AMP deaminase of a low yield of the sequence (LTPTDX) corresponding to that of HPRG N-terminus, it can be deduced that in comparison with HPRG, the putative HPRG-like component of AMP deaminase contains an additional fragment with a blocked N-terminus, which is liberated by a proteolytic process during purification of the enzyme. The implications of the association to rabbit skeletal-muscle AMP deaminase of a HPRG-like protein species are discussed.
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PMID:Association of purified skeletal-muscle AMP deaminase with a histidine-proline-rich-glycoprotein-like molecule. 930 11

The proteolytic activity of plasmin on soluble caprine beta-casein (CN) was studied in 50 mM Tris.HCI buffer, pH 8.0, at 37 degrees C. Electrophoretic studies showed that hydrolysis of this protein results in an electrophoretic pattern that is similar to the pattern obtained from plasmin hydrolysis of bovine beta-CN (gamma-CN and complementary N-terminal fragments), suggesting that plasmin probably attacks the same regions that are susceptible to cleavage in bovine beta-CN. As determined by SDS-PAGE, the gamma-like components of caprine milk consisted of two fragments with relative molecular mass of 9200 and two with relative molecular mass of 21,400 that could differ in the level of phosphorylation. Apparently, the high molecular mass components are homologous to bovine beta-CN (f 29-209) (gamma 1-CN), and the low molecular mass components are homologous to bovine beta-CN (f 106-209) and beta-CN (f 108-209) (gamma 2- and gamma 3-CN). Complementary N-terminal fragments had values for molecular masses in the range 13,600 to 8500 and urea-PAGE patterns that were more complex than those obtained in bovine casein because of the different phosphorylation levels in caprine beta-CN. These fragments were also present in the hydrolysate of whole caprine casein that had been treated with plasmin.
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PMID:Hydrolysis of caprine beta-casein by plasmin. 936 Nov 97

Stromelysin 1 (ST1) is a member of the matrix metalloproteinase (MMP) family probably involved in extracellular matrix degradation. Stromelysin 3 (ST3), considered by sequence homology to be a member of the MMP family of proteases, is specifically expressed in the stroma adjacent to the invasive tumoral cells, but its role in cancer progression remains to be elucidated. Genes encoding ST1 and ST3 were expressed in lepidopteran insect cells using the baculovirus expression vector system. Recombinant baculoviruses were obtained after cloning the full-length cDNA of ST1 and ST3 in plasmids pBacPAK1 and pBacPAK9, respectively. Sf9 insect cells infected with the recombinant baculovirus overexpressed the zymogen proST1 (60 kDa) in an insoluble form, a peak of expression being reached from 24 h postinfection. After solubilization in 8 M urea, and further refolding, activation, and purification, 0.3 mg of mature ST1 (30 kDa), purified to 90% homogeneity, was obtained per 5 x 10(8) infected cells. Recombinant ST1 exhibited proteolytic activity on alpha2-macroglobulin, casein, fibronectin, alpha1-antitrypsin, and laminin. The recombinant zymogen proST3 (55 kDa) was expressed as a soluble form in insect cells, maximal expression occurring at 72 h postinfection. After purification to 95% homogeneity, 2.5 mg of proST3 was obtained per 5 x 10(8) infected cells. A number of proteases including plasmin, urokinase, and ST1 were shown to be able to cleave proST3 giving rise to defined bands of 50-30 kDa. The ST3 mature form of 45 kDa (mST3) was also expressed in the baculovirus system and the obtained protein, 2. 5 mg per 5 x 10(8) infected cells purified to 80% homogeneity, was shown to be active on both casein degradation and alpha2-macroglobulin entrapment assays. Our results suggest that the baculovirus system offers a convenient and efficient means to produce ST1 and ST3 in order to carry out further biochemical studies.
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PMID:Expression and purification of human stromelysin 1 and 3 from baculovirus-infected insect cells. 967 69

Human tissue factor pathway inhibitor-2 (TFPI-2)/matrix-associated serine protease inhibitor (MSPI), a Kunitz-type serine protease inhibitor, inhibits plasmin, trypsin, chymotrypsin, plasma kallikrein, cathepsin G, and factor VIIa-tissue factor complex. The mature protein has a molecular mass of 32-33 kDa, but exists in vivo as two smaller, underglycosylated species of 31 and 27 kDa. TFPI-2/MSPI triplet is synthesized and secreted by a variety of cell types that include epithelial, endothelial, and mesenchymal cells. Because the majority (75-90%) of TFPI-2/MSPI is associated with the extracellular matrix (ECM), we examined which components of the ECM bind TFPI-2/MSPI. We found that TFPI-2/MSPI bound specifically to heparin and dermatan sulfate. Interaction of these two glycosaminoglycans (GAGs) with TFPI-2/MSPI involved one or more common protein domains, as evidenced by cross-competition experiments. However, binding affinity for TFPI-2/MSPI with heparin was 250-300 times greater than that for TFPI-2/MSPI with dermatan sulfate. Binding of TFPI-2/MSPI to GAGs was inhibited by NaCl or arginine but not by glucose, mannose, galactose, 6-aminohexanoic acid, or urea, suggesting that arginine-mediated ionic interactions participate in the GAG binding of TFPI-2/MSPI. This supposition was supported by the observation that only NaCl or arginine could elute the TFPI-2/MSPI protein triplet from an ECM derived from human dermal fibroblasts. Reduced TFPI-2/MSPI did not bind to heparin, suggesting that proper disulfide pairings and conformation are essential for matrix binding. To determine whether heparin modulates the activity of TFPI-2/MSPI, we determined the rate of inhibition of plasmin by the inhibitor with and without heparin and found that TFPI-2/MSPI is more active in the presence of heparin. Collectively, our results demonstrate that conformation-dependent arginine-mediated ionic interactions are responsible for the TFPI-2/MSPI triplet binding to fibroblast ECM, heparin, and dermatan sulfate and that heparin augmented the rate of inhibition of plasmin by TFPI-2/MSPI.
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PMID:Matrix localization of tissue factor pathway inhibitor-2/matrix-associated serine protease inhibitor (TFPI-2/MSPI) involves arginine-mediated ionic interactions with heparin and dermatan sulfate: heparin accelerates the activity of TFPI-2/MSPI toward plasmin. 1049 84

We report the expression of tissue factor pathway inhibitor-2 (TFPI-2) (also known as PP-5, placental protein-5; MSPI, matrix-associated serine protease inhibitor) in E. coli as a 25-kDa nonglycosylated protein with a glycine substituted for aspartic acid at the amino terminus. High-level expression of TFPI-2 was obtained with pRE1 expression vector under the transcriptional and translational controls of the lambdaP(L) promoter and lambdacII ribosome-binding site, respectively, with ATG initiation codon. TFPI-2 was produced as inclusion bodies and accounted for 25-30% of the total E. coli proteins. The inclusion bodies containing TFPI-2 were solubilized with urea, sulfitolyzed, purified, and refolded through a disulfide interchange reaction. The refolded E. coli TFPI-2 inhibited plasmin with an inhibition constant (K(i)) of 5 nM that is similar with the TFPI-2 expressed in a mammalian system. The refolded E. coli TFPI-2 bound heparin and also inhibited plasmin, regardless of whether the enzyme was in the fluid phase or was bound to the membranes of HT-1080 fibrosarcoma cells. In addition, refolded E. coli TFPI-2 inhibited radiolabeled matrix degradation and Matrigel matrix invasion by HT-1080 fibrosarcoma cells and B16-F10 melanoma cells. Together, our results suggest that glycosylation is not essential for antiprotease, antitumor, and matrix-binding activities of TFPI-2. Based on these collective data, we conclude that a biologically active nonglycosylated TFPI-2 can be produced in E. coli and that the protein can be produced in high-enough quantities to conduct in vivo studies for determination of the role of this inhibitor in tumor invasion and metastasis.
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PMID:Prokaryotic expression, purification, and reconstitution of biological activities (Antiprotease, antitumor, and heparin-binding) for tissue factor pathway inhibitor-2. 1102 24


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