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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recombinant clones with cDNA inserts coding for a new serine protease (hepsin) have been isolated from cDNA libraries prepared from human liver and hepatoma cell line mRNA. The total length of the cDNA is approximately 1.8 kilobases and includes a 5' untranslated region, 1251 nucleotides coding for a protein of 417 amino acids, a 3' untranslated region, and a poly(A) tail. The amino acid sequence coded by the cDNA for hepsin shows a high degree of identity to pancreatic trypsin and other serine proteases present in plasma. It also exhibits features characteristic of zymogens to serine proteases in that it contains a cleavage site for protease activation and the highly conserved regions surrounding the His, Asp, and Ser residues that participate in enzyme catalysis. In addition, hepsin lacks a typical amino-terminal signal peptide. Hydropathy analysis of the protein sequence, however, revealed a very hydrophobic region of 27 amino acids starting 18 residues downstream from the apparent initiator Met. This region may serve as an internal signal sequence and a transmembrane domain. This putative transmembrane domain could be involved in anchoring hepsin to the cell membrane and orienting it in such a manner that its carboxyl terminus, containing the catalytic domain, is extracellular.
...
PMID:A novel trypsin-like serine protease (hepsin) with a putative transmembrane domain expressed by human liver and hepatoma cells. 283 76

A novel serine proteinase, designated as prostasin, has been purified from human seminal fluid to apparent homogeneity by DEAE-Sepharose CL-6B and aprotinin-affinity chromatography. The purified protein migrates as two close bands with an apparent molecular mass of 40 kDa on SDS-polyacrylamide gel electrophoresis under reducing conditions. It can be labeled with [14C]diisopropyl fluorophosphate and has a pI ranging from 4.5 to 4.8. Sequence analysis reveals that the two protein bands have an identical NH2-terminal amino acid sequence which is different from any known protein sequence in the SwissPro or GenBank data base. The NH2-terminal 20-amino acid sequence shares 50-55% identity with human alpha-tryptase, elastase 2A and 2B, chymotrypsin, acrosin, and the catalytic chains of hepsin, plasma kallikrein, and coagulation factor XI. Prostasin has trypsin-like activity with a pH optimum of 9.0, hydrolyzing peptidyl fluorogenic substrates: D-Pro-Phe-Arg-MCA, D-Phe-Phe-Arg-MCA, D-Val-Leu-Arg-MCA, and Z-Gly-Pro-Arg-AFC. It is inhibited by aprotinin, antipain, leupeptin, and benzamidine. The tissue distribution of prostasin was determined by a newly developed radioimmunoassay. Linear displacement curves for immunoreactive prostasin in body fluids and tissues were parallel with the standard curve of purified prostasin, indicating their immunological identity. Immunoreactive prostatin levels were 8.61 +/- 0.42 microgram/ml in the seminal fluid and 0.201 +/- 0.029 microgram/ml in urine. Prostasin is present at high levels in the prostate gland (143.7 +/- 15.9 ng/mg protein), moderate levels (2-6 ng/mg protein) in colon, lung, kidney, pancreas, salivary gland, liver, and bronchi, but it is not detected in the brain, muscle, testis, ventricle, atrium, and aorta. Immunohistochemical localization reveals that prostasin is present in epithelial cells and ducts of the prostate gland. These studies indicate that prostasin purified from seminal fluid is a novel serine proteinase and originates from the prostate gland.
...
PMID:Prostasin is a novel human serine proteinase from seminal fluid. Purification, tissue distribution, and localization in prostate gland. 803 38

Hepsin, a putative cell-surface serine proteinase, has been isolated from the microsomal membranes of rat liver and purified to homogeneity by hydroxyapatite, DEAE-Sepharose, and benzamidine-Sepharose chromatography. The course of purification was monitored using antibodies raised against a 20-mer peptide at the C-terminus of rat hepsin, and the identity of the purified protein was confirmed by partial amino-acid sequencing. A single-chain precursor of ca. 50 kDa found in the microsomes underwent spontaneous maturation in the course of purification so that the last, affinity chromatography, step recovered only the mature form which dissociated to subunits of 31 and 19 kDa under reducing SDS-PAGE. Proteinase digestion experiments with microsomal vesicles are consistent with the luminal orientation of the precursor C-terminus, which would result in its extracellular orientation upon transportation to the cell surface. [3H]diisopropylfluorophosphate covalently binds to the large subunit showing it to be the catalytic one. The N-terminal sequencing of this subunit demonstrates that the zymogen is converted to the active serine proteinase by cleavage at the Arg161-Ile162 site. Activity measurements with short synthetic peptides show that the enzyme cleaves after basic amino-acid residues, Arg being preferable to Lys. The inhibition pattern is typical of trypsin-like serine proteinases. The pH-dependence of activity within the range pH 6-9 has no maximum, the activity increasing continuously with pH. These results are consistent with the earlier predictions based on hepsin amino-acid sequence and elucidate the specificity and other earlier unknown enzymatic and molecular properties of the enzyme.
...
PMID:Purification and characterization of hepsin from rat liver microsomes. 900 40

Previously we isolated a trypsin-like enzyme designated human airway trypsin-like protease from the sputum of patients with chronic airway diseases. This paper describes the cDNA cloning, characterization of the primary protein structure deduced from the cDNA, and gene expression of this enzyme in various human tissues. We obtained an entire 1517-base pair sequence of cDNA with an open reading frame encoding a polypeptide with 418-amino acid residues. The polypeptide consisted of a 232-residue catalytic region and a 186-residue noncatalytic region with a hydrophobic putative transmembrane domain near the NH2 terminus. The polypeptide was suggested to be a type II integral membrane protein in which the COOH-terminal catalytic region is extracellular. Therefore, this protein is thought to be synthesized as a membrane-bound precursor and to mature to a soluble and active protease by limited proteolysis. It showed 29-38% identity in the sequence of the catalytic region with human hepsin, enteropeptidase, acrosin, and mast cell tryptase. The noncatalytic region had little similarity to other known proteins. In Northern blot analysis a transcript of 1.9 kilobases was detectable most prominently in the trachea among 17 human tissues examined.
...
PMID:Cloning and characterization of the cDNA for human airway trypsin-like protease. 956 16

Hepsin is a type II transmembrane serine protease abundantly expressed on the surface of hepatocytes. Biochemical studies have shown that hepsin is an enzyme of 51 kDa with the trypsin-like substrate specificity. Several in vitro studies have suggested that hepsin may play a role in blood coagulation, hepatocyte growth, and fertilization. To determine the functional importance of hepsin, hepsin-deficient mice were generated by homologous recombination. Homozygous hepsin-/- mice were viable and fertile, and grew normally. When analyzed in hemostasis assays, such as tail bleeding time and plasma clotting times, and in vivo modes, such as disseminated intravascular coagulation, septic shock, and acute liver regeneration, hepsin-/- mice had similar phenotypes as wild-type controls. Liver weight and serum concentrations of liver-derived proteins or enzymes were also similar in hepsin-/- and wild-type mice. No abnormalities were identified in major organs in hepsin-/- mice in histological examinations. These results indicate that hepsin is not an essential enzyme for normal hemostasis, embryogenesis, and maintenance of normal liver function. Unexpectedly, serum concentrations of bone-derived alkaline phosphatase were approximately two-fold higher in both male and female hepsin-/- mice than those in wild-type controls. The underlying mechanism for this phenotype and long-term effects of hepsin deficiency remain to be determined.
...
PMID:Gene targeting in hemostasis. Hepsin. 1117 58

A cDNA encoding a novel serine protease, which we designated spinesin, has been cloned from human spinal cord. The longest open reading frame was 457 amino acids. A homology search revealed that the human spinesin gene was located at chromosome 11q23 and contained 13 exons, the gene structure being similar to that of TMPRSS3 whose gene is also located on 11q23. Spinesin has a simple type II transmembrane structure, consisting of, from the N terminus, a short cytoplasmic domain, a transmembrane domain, a stem region containing a scavenger receptor-like domain, and a serine protease domain. Unlike TMPRSS3, it carries no low density lipoprotein receptor domain in the stem region. The extracellular region carries five N-glycosylation sites. The sequence of the protease domain carried the essential triad His, Asp, and Ser and showed some similarity to that of TMPRSS2, hepsin, HAT, MT-SP1, TMPRSS3, and corin, sharing 45.5, 41.9, 41.3, 40.3, 39.1, and 38.5% identity, respectively. The putative mature protease domain preceded by H(6)DDDDK was produced in Escherichia coli, purified, and successfully activated by immobilized enterokinase. Its optimal pH was about 10. It cleaved synthetic substrates for trypsin, which is inhibited by p-amidinophenylmethanesulfonyl fluoride hydrochloride but not by antipain or leupeptin. Northern blot analysis against mRNA from human tissues including liver, lung, placenta, and heart demonstrated a specific expression of spinesin mRNA in the brain. Immunohistochemically, spinesin was predominantly expressed in neurons, in their axons, and at the synapses of motoneurons in the spinal cord. In addition, some oligodendrocytes were clearly stained. These results indicate that spinesin is transported to the synapses through the axons after its synthesis in the cytoplasm and may play important roles at the synapses. Further analyses are required to clarify its roles at the synapses and in oligodendrocytes.
...
PMID:Spinesin/TMPRSS5, a novel transmembrane serine protease, cloned from human spinal cord. 1174 86

In order to examine the possible participation of trypsin-like proteases in the onset and progress of muscular dystrophy, we investigated the expression of the trypsin-like protease in muscular tissues in mdx mice. We found that the mRNAs of several trypsin-like proteases, including hepsin and t-PA, were expressed in the muscular tissues of mdx mice, but at levels not significantly different from normal mice. Since the enzymatic properties of dystrypsin, a muscle trypsin-like protease activated before onset of the disease, are similar to those of thrombin, we investigated the expression pattern of thrombin in mdx mouse muscles. The results showed that prothrombin mRNA is up-regulated in mdx mice at 20-30 days of age but not before the age of 15 days (preclinical). Since protease nexin-1 (PN-1) is known to be a physiological inhibitor of thrombin, we also examined the expression pattern of PN-1. We found that PN-1 transcription and translation is down-regulated in the muscular tissues of mdx mice, before the onset of clinical symptoms. These results suggest that thrombin may be involved in the progression of muscular dystrophy or the regeneration of muscle fibers after the onset of the disease and that the reduced level of PN-1 may enhance the activities stimulate the activities of muscle proteases, including dystrypsin, at a preclinical stage in mdx mice.
...
PMID:Expression of trypsin-like proteases and protease nexin-1 in mdx mouse muscles. 1473 57

Hepatocyte growth factor activator (HGFA) is a serine protease that converts hepatocyte growth factor (HGF) into its active form. When activated HGF binds its cognate receptor Met, cellular signals lead to cell growth, differentiation, and migration, activities which promote tissue regeneration in liver, kidney and skin. Intervention in the conversion of HGF to its active form has the potential to provide therapeutic benefit where HGF/Met activity is associated with tumorigenesis. To help identify ways to moderate HGF/Met effects, we have determined the molecular structure of the protease domain of HGFA. The structure we determined, at 2.7 A resolution, with no pseudo-substrate or inhibitor bound is characterized by an unconventional conformation of key residues in the enzyme active site. In order to find whether this apparently non-enzymatically competent arrangement would persist in the presence of a strongly-interacting inhibitor, we also have determined, at 2.6 A resolution, the X-ray structure of HGFA complexed with the first Kunitz domain (KD1) from the physiological inhibitor hepatocyte growth factor activator inhibitor 1B (HAI-1B). In this complex we observe a rearranged substrate binding cleft that closely mirrors the cleft of other serine proteases, suggesting an extreme conformational dynamism. We also characterize the inhibition of 16 serine proteases by KD1, finding that the previously reported enzyme specificity of the intact extracellular region of HAI-1B resides in KD1 alone. We find that HGFA, matriptase, hepsin, plasma kallikrein and trypsin are potently inhibited, and use the complex structure to rationalize the structural basis of these results.
...
PMID:Conformational lability in serine protease active sites: structures of hepatocyte growth factor activator (HGFA) alone and with the inhibitory domain from HGFA inhibitor-1B. 1571 85

Hepsin is a membrane-anchored, trypsin-like serine protease with prominent expression in the human liver and tumours of the prostate and ovaries. To better understand the biological functions of hepsin, we identified macromolecular substrates employing a tetrapeptide PS-SCL (positional scanning-synthetic combinatorial library) screen that rapidly determines the P1-P4 substrate specificity. Hepsin exhibited strong preference at the P1 position for arginine over lysine, and favoured threonine, leucine or asparagine at the P2, glutamine or lysine at the P3, and proline or lysine at the P4 position. The relative activity of hepsin toward individual AMC (7-amino-4-methylcoumarin)-tetrapeptides was generally consistent with the overall peptide profiling results derived from the PC-SCL screen. The most active tetrapeptide substrate Ac (acetyl)-KQLR-AMC matched with the activation cleavage site of the hepatocyte growth factor precursor sc-HGF (single-chain HGF), KQLR downward arrowVVNG (where downward arrow denotes the cleavage site), as identified by a database analysis of trypsin-like precursors. X-ray crystallographic studies with KQLR chloromethylketone showed that the KQLR peptide fits well into the substrate-binding cleft of hepsin. This hepsin-processed HGF induced c-Met receptor tyrosine phosphorylation in SKOV-3 ovarian cancer cells, indicating that the hepsin-cleaved HGF is biologically active. Activation cleavage site mutants of sc-HGF with predicted non-preferred sequences, DPGR downward arrowVVNG or KQLQ downward arrowVVNG, were not processed, illustrating that the P4-P1 residues can be important determinants for substrate specificity. In addition to finding macromolecular hepsin substrates, the extracellular inhibitors of the HGF activator, HAI-1 and HAI-2, were potent inhibitors of hepsin activity (IC50 4+/-0.2 nM and 12+/-0.5 nM respectively). Together, our findings suggest that the HGF precursor is a potential in vivo substrate for hepsin in tumours, where hepsin expression is dysregulated and may influence tumorigenesis through inappropriate activation and/or regulation of HGF receptor (c-Met) functions.
...
PMID:Hepatocyte growth factor is a preferred in vitro substrate for human hepsin, a membrane-anchored serine protease implicated in prostate and ovarian cancers. 1583 37

Rat liver microsomal glutathione S-transferase (MGST1) is known to be activated by trypsin, however, it has not been clarified whether MGST1 is activated by a protease present in liver. In the present study we purified the MGST1 activating protease from liver microsomes and finally identified that the protease is hepsin, a type II transmembrane serine protease. When the protease was incubated with the purified MGST1 or liposomal MGST1 at 4 degrees C, MGST1 activity was increased 3-4.5 fold after 3-6 d. In electrophoretic and immunoblot analyses after the incubation of MGST1 with the protease MGST1 dimer and its degraded fragment were detected. These results suggest that the rat liver microsomal hepsin functions as MGST1 activating/degrading enzyme.
...
PMID:Purification of liver serine protease which activates microsomal glutathione S-transferase: possible involvement of hepsin. 1665 11


1 2 3 Next >>

---