Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.11 (CD10)
 9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have cloned a full length cDNA for human leukocyte elastase (HLE, EC 3.4.21.37)/medullasin from the cDNA library of human leukemic cell line, ML3. Recombinant plasmid for the expression of HLE cDNA in eukaryotic cells was constructed in which HLE cDNA was fused in a frame to a leader sequence of human interleukin-2 (IL-2). COS-1 cells, transfected with the plasmid, secreted fusion protein consists of N-terminal 8 amino acid (aa) residues of human IL-2 and 238 aa residues of HLE. As the fusion protein was designed to be connected through lysine residue, elastase activity was generated after digestion of the fusion protein with lysyl-endopeptidase.
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PMID:Functional expression of human leukocyte elastase (HLE)/medullasin in eukaryotic cells. 232 78

Limited proteolysis of T-kininogen by heterologous and homologous endopeptidases (bovine trypsin, human leukocyte elastase, rat submaxillary gland endopeptidase k, and rat mast cell chymase) produced similar fragmentation. Amino-terminal sequence analysis of whole T-kininogen lysates and purified proteolytic fragments identified four susceptible regions which contained all the preferential cleavage sites for these proteinases. Two of these susceptible regions were close to the junction between heavy chain cystatin-like domains, the third was in the kinin-containing region, and the fourth was close to the carboxyl terminus of the T-kininogen light chain. There was only one primary site for each proteinase in the kinin-containing region, which explains why catalytic amounts of these proteinases did not release immunoreactive kinin from this kininogen. However, preferential cleavage of T-kininogen close to the junction between cystatin-like domains released fragments which, provided they included cystatin-like domains 2 and/or 3, strongly inhibited papain and cathepsin L. The fragments were inhibitory even when parts of the amino-terminal ends of the domains were lacking. The highly conserved glycyl residue, thought to be involved in the inhibitory reactive site of cystatin-like inhibitors, was not required in purified domain 3 for inhibition of cathepsin L.
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PMID:Limited proteolysis of T-kininogen (thiostatin). Release of comparable fragments by different endopeptidases. 264 33

N-oleoyl-heparin derivatives differing in their oleic acid and sulfate contents were synthesized and studied for their abilities to inhibit human leukocyte elastase (HLE), human leukocyte cathepsin G (CatG) and porcine pancreatic elastase (PPE) at pH 8.0, ionic strength 0.05 M and 37 degrees. Heparin (Hep) as well as N-oleoyl-heparins behaved as tight-binding, hyperbolic noncompetitive inhibitors of HLE (KiHep = 75 pM) and CatG (KiHep < 25 pM). The main driving force for the interaction between enzymes and glycosaminoglycans was electrostatic in nature. Under the condition [enzyme] >> Ki, the stoichiometries of the interaction with Hep were 1:2 (Hep:HLE) and 1:4 (Hep:CatG). Coupling one oleic acid residue to three disaccharide units of partially N-desulfated Hep, Ol1:3Hep, lowered HLE inhibition (Ki = 0.3 nM) and the stoichiometry of binding was reduced to 1:1. Re-N-sulfation of a similar derivative, Ol1:5Hep(SO4), containing one fatty acid residue for five disaccharide units, led to a substance with similar HLE inhibitory characteristics as Hep (Ki = 92 pM) and stoichiometry 1:2. Ol1:5Hep(SO4) was also a more efficient inhibitor of CatG (Ki < 33 pM) than Ol1:3Hep (Ki = 9.5 nM). The residual activities of N-oleoyl-Hep complexes with CatG were much lower than the corresponding activities in the presence of Hep. While oleate and Hep could not inhibit PPE, N-oleoyl-Hep, independently of fatty acid substitution and sulfate content, could inhibit this enzyme with Ki congruent to 60 nM and low residual activity. The efficient endopeptidase inhibitory characteristics of N-oleoyl-Hep derivatives, together with their non-anticoagulant properties and their capacity to interact with elastin, may be therapeutically useful in connective tissue degenerative diseases.
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PMID:Inhibition of the human leukocyte endopeptidases elastase and cathepsin G and of porcine pancreatic elastase by N-oleoyl derivatives of heparin. 824 Apr 9

Several forms of perturbation result in the release of bioactive molecules into the microenvironment of injured cells to mediate the inflammatory or reparative reactions which restore normal tissue structure and function. Amongst other products, ultraviolet irradiation (UV) causes the release of the growth factor TGF alpha from a variety of epithelial cell sources, apparently by a post-translational mechanism. Here we have explored the hypothesis that UV results in the activation of cell surface proteases which may then be capable of excising mature TGF alpha from its plasma membrane-bound precursor. Using a recently described, sensitive assay of peptidase activity tailored to the substrate requirements for cleavage of the scissile bonds in proTGF alpha, we have found that nonlethal fluences of UV (< 12 Jm-2) to HeLa cell cultures are followed by large increases in cell surface proteolytic activities. Amongst these, endopeptidase activity produces a similar product profile from the nonapeptide substrate to that of human leukocyte elastase, an enzyme previously shown to be capable of releasing a bioactive, mature form of TGF alpha from its cell-bound precursor. However, in addition to this candidate "TGFase" activity, cell surface aminopeptidase activity was also very significantly increased. The increase in the two classes of peptidase function differed in the timing of their responses. Aminopeptidase activation occurred immediately following UV, peaking after some 15-20 h, whereas the increase in endopeptidase activity lagged 6 h behind, cresting after 20-24 h. No evidence for a role for aminopeptidase in the activation of the endopeptidase could be found. Also, there was no increase in the total proteolytic activity demonstratable in cell extracts following UV. Attempts to interrupt the UV peptidase activation by inhibiting protein synthesis with cycloheximide were unsuccessful; rather, the inhibitor itself caused an increase in both classes of peptidase activity during the first 20 h. Unlike the UV response, both the aminopeptidase and endopeptidase ectoactivities increased simultaneously within a few hours of introducing cycloheximide into the medium of unirradiated cultures. The cycloheximide induced activity peaked after 20 h. Interestingly, cycloheximide alone has previously been shown to potentiate TGF alpha release from a cell line producing its precursor constitutively. These data suggest that both UV and cycloheximide can initiate reactions in HeLa cells which result in ectopeptidase activation of a global nature. Since both agents result in rapid interruption of DNA synthesis, it is possible that this cell surface proteolytic response may be analogous to, or part of, the "mammalian genetic stress response".(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Low fluences of ultraviolet irradiation stimulate HeLa cell surface aminopeptidase and candidate "TGF alpha ase" activity. 843 38

Thirty analogues of poststatin were synthesized, and their inhibitory activities against prolyl endopeptidase, human leukocyte elastase and cathepsin B were measured. The alpha-ketone was essential and the S configuration was preferable to the R configuration in the beta-substituted-beta-amino-alpha-oxopropionic acid moiety of poststatin analogues for endopeptidase inhibitory activity. The analogue in which the D-leucine residue of poststatin was replaced by L-leucine showed strong inhibitory activity to cathepsin B. Introduction of an aromatic group into the P4 position and proline into the P2 position increased inhibitory activity to elastase. Benzyloxycarbonyl-L-homophenylalanyl-(RS)- 3-amino-2-oxovaleryl-D-leucyl-L-valine was about 6 times more active to prolyl endopeptidase than natural poststatin.
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PMID:Poststatin, a new inhibitor of prolyl endopeptidase. V. Endopeptidase inhibitory activity of poststatin analogues. 893 23

We report the production of human mucus proteinase inhibitor (MPI) by the filamentous fungus Aspergillus niger to test the ability of this host organism to secrete low molecular weight, highly disulfide-bonded proteins in biologically active conformation. Fungal transformants have been obtained with an expression cassette consisting of a chimeric gene founded on a mpi cDNA, encoding mature MPI, fused in frame to sequences encoding A. niger glucoamylase (glaA), separated by a KEX2-like processing sequence. Expression of the glucoamylase fusion gene in these transformants resulted in secretion of MPI into the growth medium with yields up to 3 mg 1-1. N-terminal sequence analysis of the purified inhibitor confirmed that the glucoamylase-MPI fusion protein was correctly processed to mature MPI by a KEX2-type endopeptidase present in A. niger. Furthermore, recombinant MPI retains full inhibitory activity against chymotrypsin and leukocyte elastase indicating that the protein was folded properly.
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PMID:Secretion of active human mucus proteinase inhibitor by Aspergillus niger after KEX2-like processing of a glucoamylase-inhibitor fusion protein. 908 9