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

---

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

Amyloid beta protein (beta/A4) is deposited in senile plaques of patients with Alzheimer's disease. This protein is derived from a larger membrane-associated protein, termed amyloid precursor protein (APP). The constitutive processing of APP occurs at the central portion of beta/A4, resulting in the release of large N-terminal peptides. We have purified these peptides from the culture medium of cDNA-transfected COS-1 cells. Some of the isoforms contain the Kunitz-type protease inhibitor (KPI) domain and strongly inhibit trypsin, chymotrypsin and plasmin, but do not inhibit kallikrein, prolyl endopeptidase or granzyme A. The peptides also do not inhibit cysteine proteases such as cathepsin B or calpain. Soluble APPs lacking the KPI domain fail to inhibit any of these proteases. The results indicate that the KPI domain in soluble APPs has protease inhibitory activity against certain serine proteases.
...
PMID:Inhibitory spectra of purified protease nexin-II and related proteins towards cellular proteinases. 790 50

The Kunitz-type protease inhibitor domain from a recently identified homolog of the Alzheimer amyloid precursor protein (APPH KPI) was expressed in yeast, purified and characterized. Its inhibition profile towards several serine proteases was studied and compared to that of APP KPI, the Kunitz domain from the Alzheimer amyloid precursor protein. APPH KPI was shown to inhibit proteases with trypsin-like specificity with an inhibitor profile resembling that of the APP KPI domain. The KPI domains from APP and APPH inhibited trypsin (Ki = 0.02 nM), and plasma kallikrein (Ki = 86 nM) with approximal equal affinity. In comparison to APP KPI (Ki = 82 nM) the KPI domain of the homolog, APPH KPI, (Ki = 8.8 nM) was a more potent inhibitor of glandular kallikrein. APPH KPI was a less potent inhibitor of chymotrypsin than APP KPI (Ki = 78 nM as compared to Ki = 6 nM), plasmin (Ki = 81 nM as compared to 42 nM), and factor XIa (Ki = 14 nM as compared to Ki = 0.7 nM). The affinity of factor XIa for APPH KPI is sufficiently high to allow for an interaction in the blood. It is, however, well possible that the physiological protease ligand for the receptor-like APPH protein has yet to be identified.
...
PMID:Expression, purification and characterization of a Kunitz-type protease inhibitor domain from human amyloid precursor protein homolog. 830 56

Interrogation of the public expressed sequence tag (EST) data base with the sequence of preproaprotinin identified ESTs encoding two potential new members of the Kunitz family of serine protease inhibitors. Through reiterative interrogation, an EST contig was obtained, the consensus sequence from which encoded both of the novel Kunitz domains in a single open reading frame. This consensus sequence was used to direct the isolation of a full-length cDNA clone from a placental library. The resulting cDNA sequence predicted a 252-residue protein containing a putative NH2-terminal signal peptide followed sequentially by each of the two Kunitz domains within a 170-residue ectodomain, a putative transmembrane domain, and a 31-residue hydrophilic COOH terminus. The gene for this putative novel protein was mapped by use of a radiation hybrid panel to chromosome 19q13, and Northern analysis showed that the corresponding mRNA was expressed at high levels in human placenta and pancreas and at lower levels in brain, lung, and kidney. An endogenous soluble form of this protein, which was designated as placental bikunin, was highly purified from human placenta by sequential kallikrein-Sepharose affinity, gel filtration, and C18 reverse-phase chromatography. The natural protein exhibited the same NH2 terminus as predicted from the cloned cDNA and inhibited trypsin, plasma kallikrein, and plasmin with IC50 values in the nanomolar range.
...
PMID:Identification and cloning of human placental bikunin, a novel serine protease inhibitor containing two Kunitz domains. 911 94

We reported previously the cloning of a novel human serine protease inhibitor containing two Kunitz-like domains, designated as placental bikunin, and the subsequent purification of a natural counterpart from human placental tissue (Marlor, C. W., Delaria, K. A., Davis, G., Muller, D. K., Greve, J. M., and Tamburini, P. P. (1997) J. Biol. Chem. 272, 12202-12208). In this report, the 170 residue extracellular domain of placental bikunin (placental bikunin(1-170)) was expressed in baculovirus-infected Sf9 cells using its putative signal peptide. The resulting 21.3-kDa protein accumulated in the medium with the signal peptide removed and could be highly purified by sequential kallikrein-Sepharose and C18 reverse-phase chromatography. To provide insights as to the potential in vivo functions of this protein, we performed an extensive investigation of the inhibitory properties of recombinant placental bikunin(1-170) and both of its synthetically prepared Kunitz domains. All three proteins inhibited a number of serine proteases involved in the intrinsic pathway of blood coagulation and fibrinolysis. Placental bikunin(1-170) formed inhibitor-protease complexes with a 1:2 stoichiometry and strongly inhibited human plasmin (Ki = 0.1 nM), human tissue kallikrein (Ki = 0.1 nM), human plasma kallikrein (Ki = 0.3 nM) and human factor XIa (Ki = 6 nM). Conversely, this protein was a weaker inhibitor of factor VIIa-tissue factor (Ki = 1.6 microM), factor IXa (Ki = 206 nM), factor Xa (Ki = 364 nM), and factor XIIa (Ki = 430 nM). This specificity profile was to a large extent mimicked, albeit with reduced potency, by the individual Kunitz domains. As predicted from this in vitro specificity profile, recombinant placental bikunin(1-170) prolonged the clotting time in an activated partial thromboplastin time assay.
...
PMID:Characterization of placental bikunin, a novel human serine protease inhibitor. 911 95

Tissue factor pathway inhibitor-2 (TFPI-2), also known as placental protein 5, is a serine protease inhibitor consisting of three tandemly-arranged Kunitz-type protease inhibitor domains. While TFPI-2 is a potent inhibitor of trypsin, plasmin, kallikrein, and factor XIa in the test tube, the function of this inhibitor in vivo remains unclear. In the present study, we investigated the synthesis and secretion of TFPI-2 by cultured endothelial cells derived from human umbilical vein, aorta, saphenous vein, and dermal microvessels to gain insight into its biological function. While all endothelial cells examined synthesized and secreted TFPI-2, dermal microvascular endothelial cells synthesized threefold to sevenfold higher levels of TFPI-2. Approximately 60% to 90% of the TFPI-2 secreted by endothelial cells was directed to the subendothelial extracellular matrix (ECM). When cultured human umbilical vein endothelial cells were stimulated with inflammatory mediators such as phorbol 12-myristate,13-acetate; endotoxin; and tumor necrosis factor-alpha, TFPI-2 synthesis by these cells increased twofold to 14-fold. Recombinant TFPI-2 bound to dermal microvascular endothelial cell monolayers and its ECM in a specific, dose-dependent, and saturable manner with Kd values of 21 and 24 nmol/L, respectively. TFPI-2 interacted with 4.5 X 10(10) sites/cm2 (3 X 10[5] sites/cell) and 2.3 X 10(11) sites/cm2 on endothelial cells and ECM, respectively. In the presence of rabbit anti-TFPI-2 IgG, but not preimmune IgG, endothelial cells dissociated from the culture flask in a time- and IgG concentration-dependent manner. Our findings provide evidence that endothelial cell-derived TFPI-2 is primarily secreted into the abluminal space and presumably plays an important role in maintaining the integrity of the ECM essential for cell attachment.
...
PMID:Quantification and characterization of human endothelial cell-derived tissue factor pathway inhibitor-2. 944 54

Tissue factor pathway inhibitor (TFPI), a Kunitz-type protease inhibitor with three tandem inhibitory domains (K1, K2 and K3), inhibits the initial reactions of the extrinsic blood coagulation pathway through its K1 and K2 domains. We prepared and characterized a monoclonal antibody (Mab8-1) against TFPI-factor Xa (TFPI-Xa) complex. The reactivities of Mab8-1 toward TFPI-Xa complex, TFPI without C-terminal (TFPI-C)-Xa complex, K1K2-Xa complex and K2K3-Xa complex were examined using a surface plasmon resonance analysis (Biacore). The Biacore system allowed a quantitative analysis of antibody-antigen interaction, in real time, from which the association and dissociation rate constants could readily be obtained. The bindings of Mab8-1 to TFPI-Xa complex, TFPI-C-Xa complex and K2K3-Xa complex were each concentration-dependent. However, no binding of Mab8-1 to the K1K2-Xa complex was observed. The binding of Mab8-1 to TFPI or Xa was also not observed. These results suggested that the epitope for Mab8-1 was exposed in the K3 domain of TFPI, which was generated by the conformational change after the formation of TFPI-Xa complex. We then developed an enzyme-linked immunosorbent assay method specific for TFPI-Xa complex using Mab8-1, and we used this assay to measure plasma levels of TFPI-Xa. The normal range assessed from analyses of plasma from 30 normal healthy volunteers was 17.7-66.7 with a mean of 35.5 +/- 11.7 pmol/l. In order to asses the clinical implication of TFPI-Xa complex in the plasma of patients with thrombotic disorders, plasma concentrations were measured in 37 patients with disseminated intravascular coagulation (DIC) caused by a variety of underlying diseases. The TFPI-Xa antigen levels were significantly higher in the patients with DIC (51.9 +/- 21.6 pmol/l) and the 36 patients with pre-DIC (55.1 +/- 20.2 pmol/l) than in the 137 non-DIC patients (37.9 +/- 13.1 pmol/l). In the patients with DIC or pre-DIC, there was no significant correlation between TFPI-Xa complex and the elevated levels of thrombin-antithrombin complex, plasmin-alpha2 plasmin inhibitor complex, D-dimer, soluble fibrin monomer, soluble thrombomodulin or tissue factor. These data indicate that the plasma level of TFPI-Xa seems to be a novel independent molecular marker of DIC and pre-DIC.
...
PMID:Monoclonal antibody specific for tissue factor pathway inhibitor-factor Xa complex: its characterization and application to plasmas from patients with disseminated intravascular coagulation and pre-disseminated intravascular coagulation. 1049 12

A glycoprotein with a high inhibitory activity against trypsin was isolated in 1961 from human plasma and named inter-alpha trypsin inhibitor (ITI). Since then, several other proteins that share antigenic and structural similarities with ITI have been identified and classified as members of the ITI protein family. These glycoproteins built up from different combinations of four polypeptides HC1, HC2, HC3 and bikunin are encoded by four genes H1, H2, H3, L on three chromosomes. Bikunin has two proteinase inhibitor domains and belongs to the Kunitz-type protease inhibitor family; it displays an inhibitory activity against trypsin, leukocyte elastase and plasmin. The heavy chains do not have any protease inhibitory properties but have the capacity to interact in vitro and in vivo with hyaluronic acid. This binding promotes the stability of the extra-cellular matrix. Consequently, the ITI protein family is suspected of playing a key role in the extra-cellular matrix biology. Isolation of free heavy chains in bronchial secretions and the recent emphasis about the bikunin role in tumoral invasion should enhance the interest about ITI protein family in the pathophysiology of chronic bronchopulmonary diseases or lung cancer progression.
...
PMID:[Proteins of the inter-alpha trypsin inhibitor (ITI) family. A major role in the biology of the extracellular matrix]. 1085 62

Urinary trypsin inhibitor (UTI; Mr 40 kDa) is a Kunitz-type protease inhibitor that efficiently inhibits cell-associated trypsin and plasmin activities. The aim of this study is to examine the expression pattern of UTI in the human ovarian carcinoma ascites fluid by Western blotting, zymography, immunoprecipitation, immunohistochemistry, biochemical and gene analyses and animal experiments. We have identified and characterized the 40 kDa immunoreactive UTI (UTI(40)) and 8 kDa degradation fragment (UTI(8)) in ascites fluid. The levels of UTI(40) and UTI(8) are elevated in ascites fluid taken from patients with ovarian carcinoma relative to paired plasma samples. The UTI(40) and UTI(8) were identified immunologically by the reactivity with 2 different anti-UTI antibodies recognizing different epitopes of the UTI molecule, functionally by its ability to bind trypsin and structurally by its apparent molecular mass with and without deglycosylation treatment. The purified polypeptides have been sequenced and were identical with sequences obtained from UTI and the carboxyl-terminal domain of UTI, respectively. However, UTI mRNA was not detected in the ovarian carcinoma tissue and ovarian carcinoma cell lines examined. Based on extravasation experiments using intravenously injected biotinylated inter-alpha-trypsin inhibitor (IalphaI; a precursor of UTI), we conclude that UTI(40) and UTI(8) found in the ascites fluid may result from (i) the extravasation of plasma proteins such as IalphaI into the peritoneal cavity via hyperpermeable vessels and (ii) the subsequent degradation of IalphaI and UTI(40) by tumor cell-associated trypsin-like enzymes.
...
PMID:Identification and characterization of a Kunitz-type protease inhibitor in ascites fluid from patients with ovarian carcinoma. 1086 51

Hepatocyte growth factor activator inhibitor type-2/placental bikunin (HAI-2/PB) is a serine proteinase inhibitor that contains 2 Kunitz-domains and a presumed transmembrane domain. It has broad inhibitory spectra against various serine proteinases showing potent inhibitory activities not only to hepatocyte growth factor activator but also to plasmin, trypsin and kallikreins. In this study, we investigated the expression of HAI-2/PB in human gliomas in vivo and the effects of HAI-2/PB on the fibrinolytic and invasive capabilities of human glioblastoma cells in vitro. With RNA blot analysis, HAI-2/PB mRNA was expressed in normal brain and in low-grade astrocytomas, but was hardly detectable in anaplastic astrocytomas and glioblastomas, indicating that its expression levels were inversely correlated with the histological grade of human gliomas. To further explore the possible role of HAI-2/PB in glioma progression, cultured human glioblastoma cell lines (U251 and YKG-1) were transiently transfected with an expression vector harboring human HAI-2/PB cDNA. Subsequent analysis indicated that the expression of HAI-2/PB suppressed the fibrinolytic activities of both glioblastoma cell lines. Moreover, HAI-2/PB inhibited Matrigel invasion of U251 and YKG-1 cells by 30% and 64%, respectively. This anti-invasive effect appeared to be mediated primarily by the inhibitory activity of HAI-2/PB against the serine proteinase-dependent matrix degradation. These findings suggest that the reduced expression of HAI-2/PB is possibly involved in the progression of human gliomas.
...
PMID:Reduced expression of hepatocyte growth factor activator inhibitor type-2/placental bikunin (HAI-2/PB) in human glioblastomas: implication for anti-invasive role of HAI-2/PB in glioblastoma cells. 1143 97

Bikunin (bik), a Kunitz-type protease inhibitor, also known as urinary trypsin inhibitor, is proposed as a main participant in the inhibition of tumor cell invasion and metastasis, possibly through the direct inhibition of cell-associated plasmin activity and suppression of urokinase-type plasminogen activator (uPA) mRNA expression. In the present study, we transfected the human ovarian carcinoma cell line HRA, highly invasive cells, with an expression vector harboring a cDNA encoding for human bik. Our study was designed to investigate the effect of bik overexpression and changes in tumor cell phenotype and invasiveness in the stably transfected clones. Bik gene transfection of HRA gave the following results: 1) transfection of HRA with the bik cDNA resulted in 5 variants stably expressing functional bik; 2) bik(+) clones exhibited a significantly reduced uPA mRNA expression as compared to the parental cells; 3) bikunin negatively regulates the ERK1/2 activity; 4) secretion-blocking treatments of bik(+) clones abrogated bik-mediated suppression of ERK1/2 activation and uPA expression; 5) the regulation of invasion seen in the HRA cells is mainly mediated by the uPA-plasmin-MMP-2 system; 6) transfection of HRA with the bik gene significantly reduced invasion, but not proliferation, adhesion, or migration relative to the parental cells; and 7) animals with bik(+) clones induced reduced peritoneal dissemination and long term survival. We conclude that transfection of HRA cells with the bik cDNA constitutively suppresses ERK1/2 activation, which results in inhibition of uPA expression and subsequently reduces dissemination of bik(+) clones.
...
PMID:Suppression of invasion and peritoneal carcinomatosis of ovarian cancer cell line by overexpression of bikunin. 1256 52


1 2 Next >>

---