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:3.4.24.11 (CD10)
9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Our previous studies indicated that Arginine (Arg) plays a key nutritional role in Streptococcus sanguis P4A7 and that this organism can grow on whole casein as the sole nitrogen source. Its protease activities were therefore studied after glucose-limited continuous culture in a chemically-defined medium with either free amino acids or casein as the nitrogen source. Both culture supernatant and cell-associated endopeptidase (EP) and exopeptidase (amino-AP and carboxy-CP) activities were determined. Growth rate (mu) had little effect on EP, 75% of which was consistently in culture supernatants; AP and CP both decreased as mu was increased and both were predominantly cell-associated. At high growth pH, EP was substantially increased while AP and CP activities were optimal at pH 7. The most striking nutritional effect occurred under nitrogen limitation (glucose excess) when EP and AP were greatly increased and CP greatly decreased. It was concluded that S. sanguis is well equipped to scavenge its environment for Arg under a wide range of growth conditions.
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PMID:Some aspects of protease production by a strain of Streptococcus sanguis. 208 51

Simian Virus 40 (SV40) transformation of primary cultures of human mammary epithelial cells has yielded a cloned epithelial-like cell line and a representative, single-cell subclone. Although apparently homogeneous, both cloned cell lines can also yield small numbers of three other cell types. The more-elongated cell type can be obtained directly by replating cells from the medium of the epithelial-like cell cultures or by picking and culturing single cells to form representative lines. Immunofluorescent and immunocytochemical analysis of these cell lines growing on plastic or as tumor-nodules in nude mice for epithelial membrane antigens, various cytokeratins, various actins, laminin, Type IV collagen, the common acute lymphoblastic leukemia antigen (CALLA), and a 135-kDa glycoprotein confirm the epithelial nature of the epithelial-like cells and suggest a myoepithelial origin for the more-elongated cell type. Ultrastructural analysis largely confirms the results, although the myofilamental bundles can be scanty in the growing myoepithelial-like cells. The other two cell types are possibly related to the keratinizing and casein-secreting cells seen in the epithelial tumor-nodules before and after mating the mice, respectively. The myoepithelial-like cells produce 5- to 17-fold more laminin, Type IV collagen, CALLA, and the 135-kDa glycoprotein than the epithelial cells, and all of these antigens are preferentially found on myoepithelial cells in vivo. It is suggested that the SV40-transformed epithelial cell is an immortalized form of human mammary stem cell which can differentiate in culture and in vivo to myoepithelial-like cells.
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PMID:Isolation of simian virus 40-transformed human mammary epithelial stem cell lines that can differentiate to myoepithelial-like cells in culture and in vivo. 247 1

Three endopeptidases, proteinases A, B, and Y, were purified from baker's yeast, Saccharomyces cerevisiae. Two molecular forms of proteinase A (PRA), Mr 45,000 and 54,000, (estimated on SDS-PAGE) were obtained. Both forms were inhibited by pepstatin and other acid proteinase inhibitors. The enzyme digested hemoglobin most rapidly at pH 2.7-3.2 and casein at pH 2.4-2.8 and 5.5-6.0. The optimum pH for hydrolysis of protein substrates could be shifted to about 5 with 4-6 M urea. Urea also stimulated the enzyme activity by 30-50%. As other acid proteinases, the enzyme preferentially cleaved peptide bonds of X-Tyr and X-Phe type. A proteinase B (PRB) preparation of approximately Mr 33,000 possessed milk clotting activity and showed an inhibition pattern typical for seryl-sulfhydryl proteases. The purified enzyme could be stabilized with 40% glycerol and stored at -20 degrees C without significant loss of activity for several months. The third endopeptidase, designated PRY, of Mr 72,000 when estimated by Sephadex G-100 gel filtration, had properties resembling PRA and PRB. Similar to PRB, it could be inhibited by up to 90% with phenylmethylsulfonyl fluoride and para-chloromercuribenzoate and preferentially hydrolyzed the Leu15-Tyr16 peptide bond of the oxidized beta-chain of insulin. On the other hand, contrary to PRB, it had neither milk clotting activity nor esterolytic activity toward N-acetyl-L-tyrosine ethyl ester and N-benzoyl-L-tyrosine ethyl ester and was stable during storage at -20 degrees C without glycerol. The enzyme also showed a lower pH optimum for hydrolysis of casein yellow than PRB.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Purification and properties of three endopeptidases from baker's yeast. 266 27

A protease of molecular weight 29,000 was isolated and purified using ammonium sulphate precipitation, lentil lectin-Sepharose affinity chromatography and DEAE-5PW ion-exchange chromatography. The protease had an unusual amino acid composition including 5% serine, 6% proline and 20% tyrosine. It was a glycoprotein containing 12-15% carbohydrate by weight. Activity was optimal at 40-45 degrees C using [3H]-acetyl casein substrate and at 40-55 degrees C using [3H]-acetyl enamel protein substrate. It was irreversibly denatured at 80 degrees C and above. With [3H]-acetyl casein the pH optimum was 8.0-8.5 and with [3H]-acetyl enamel protein it was 6.0-8.0. There was no activity below pH 5.0, and irreversible denaturation occurred at pH 4.0 and below. No autodegradation occurred with storage at 4 degrees C for 30 days at pH 7.0. Phenylmethylsulphonyl fluoride, mercuric chloride, and p-aminobenzoic acid completely inactivated the protease. The enzyme had no requirement for calcium. The sites of cleavage of the oxidized B-chain of insulin were the Cys-Gly and Arg-Gly bonds. The enzyme was therefore an endopeptidase. Cleavage of Na-benzoyl-L-arginine ethyl ester, but not Na-benzoyl-L-tyrosine ethyl ester, suggests that the protease is of the trypsin family. On the basis of its physical and enzymic properties the protease is a serine proteinase and, consistent with existing terminology, has been named proteinase pemB.
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PMID:Purification and properties of a protease from developing porcine dental enamel. 268 9

The phosphoramidon-insensitive endopeptidase-2 in rat renal brush borders was investigated by immunochemical approaches with a rabbit polyclonal antibody raised to the purified enzyme released from the membrane by papain. An immunoaffinity column successfully purified the detergent-solubilized form of endopeptidase-2. This preparation had an apparent subunit Mr of 80,000, and did not show the two subunits, of Mr 80,000 and 74,000, consistently found in the papain-solubilized forms, indicating that the latter resulted from proteolysis by papain. SDS/polyacrylamide-gel electrophoresis of non-reduced samples of the enzyme revealed a band of Mr 220,000, confirming the presence of disulphide-bridged subunits. Treatment with endoglycosidases H and F generated smaller molecular forms, indicating that endopeptidase-2 contained about 30% asparagine-linked carbohydrate and that a few of these oligosaccharide chains were of the high-mannose type. Treatment with phosphatidylinositol-specific phospholipase indicated that the enzyme did not possess a glycolipid membrane anchor. A survey of rat tissues examined immunohistochemically and by immunoblotting revealed that only the kidney and intestinal tract expressed the antigen in significant amounts. Although some weak staining was seen in salivary glands and thyroid, other organs and tissues including brain and spinal cord were negative by both immunochemical techniques. In the kidney the antigen was confined to the lumen of the proximal tubule and was seen mainly in the population of juxtamedullary nephrons. In the gut, luminal staining was observed throughout its whole length, from duodenum to rectum. Excellent cross-reactivity of the antibody with Balb/c mouse tissues was observed. Immunohistochemistry of mouse kidney and gut revealed a distribution identical with that observed in the rat. Immunopurification of the detergent-solubilized mouse kidney antigen showed it to be a protein containing disulphide-linked subunits of Mr 90,000. It possessed endopeptidase-2-like activity, but was more efficient in hydrolysing azo-casein and less efficient in hydrolysing a model substrate than the rat enzyme. The close similarity between rat endopeptidase-2 and mouse meprin is further supported by these results.
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PMID:Proteins of the kidney microvillar membrane. Structural and immunochemical properties of rat endopeptidase-2 and its immunohistochemical localization in tissues of rat and mouse. 269 Aug 25

A. niger LCF 9 synthesizes a new aspergillopeptidase of potential interest in therapeutics. The properties and operating range of the enzyme were determined. It is a semi-alkaline aspergillopeptidase (EC 3.4.23.4) with one endopeptidase activity. Its pI is 4.10, its molecular weight is 21000 Da and its A1%(1 cm) at 280 nm is 9.75. It rapidly hydrolyzes casein and hemoglobin. Its optimal pH is 7.8 and optimal temperature is 45 degrees C. It is thermally labile above 40 degrees C but can be stabilized by adding calcium ions. It is inhibited by phenylmethylsulfonyl fluoride (PMSF), by ethylenediaminetetraacetic acid (EDTA) and by certain metals ions, e.g. copper, manganese and cobalt ions. It has no dipeptidase or tripeptidase activity and its esterase activity is weak. It has a high collagenase activity and is to our knowledge the only aspergillopeptidase that is active towards benzoyl-arginine p-nitroanilide (BAPNA).
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PMID:Properties of a new alkaline proteinase from Aspergillus niger. 269 84

An endopeptidase which digests denatured collagen to small, dialysable fragments was purified 2675-fold from medium that had been conditioned by the culture of fibroblasts grown from explants of human gingiva. This enzyme was inhibited by chelating agents, but not by phenylmethylsulphonyl fluoride nor by N-ethylmaleimide, and is therefore probably a metalloproteinase. It showed no demonstrable activity against native collagen or ovalbumin, while alpha-casein was digested slowly, if at all. It therefore belongs to the group of enzymes which have been called tissue gelatinases. This gelatinase was secreted in a latent form or forms and could be activated by proteolysis with trypsin. The active enzyme had an apparent molecular weight of 69 000 (gel chromatography) or 72 000 (gel electrophoresis in sodium dodecyl sulphate) and an apparent isoelectric point of 4.15.
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PMID:Purification and characterization of a gelatinase produced by fibroblasts from human gingiva. 301 48

A serine endopeptidase was partially purified from rat liver plasma membranes by using a four-step procedure: solubilization with N-lauroylsarcosine; Ultrogel AcA-34 chromatography; CM Affi-Gel blue chromatography; agarose-soybean trypsin inhibitor chromatography. This enzyme was found to hydrolyze casein and various chromogenic peptide substrates; highest activity occurred with H-D-Val-Leu-Arg-p-nitroanilide, reported to be a specific substrate for human glandular kallikreins. The enzyme was heat-sensitive, showed a pH optimum between 8.0 and 9.0 and was inhibited by D-Phe-L-Phe-L-Arg-CH2Cl, aprotinin, diisopropyl fluorophosphate (DFP), soybean trypsin inhibitor, phenylmethylsulphonyl fluoride, leupeptin, antipain and dithiothreitol. This liver plasma membrane proteinase has an apparent molecular weight of about 30 000 as determined by Ultrogel AcA-34 chromatography and by autoradiography of [3H]DFP-labelled protein electrophoresis.
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PMID:Partial purification and characterization of a serine endopeptidase from rat liver plasma membranes. 351 45

An endopeptidase (LEP-II), which has a unique substrate specificity, was purified to homogeneity by conventional chromatographic techniques from Streptococcus cremoris H61. The enzyme was a metalloendopeptidase since it was inhibited by EDTA and 1,10-phenanthroline; the metal-depleted enzyme could be fully reactivated by micromolar levels of Zn2+ and was not inhibited by specific inhibitors for serine or thiol protease. The molecular mass of the enzyme was estimated to be 80 kDa by Sephacryl S-300 gel filtration and high-performance liquid chromatography with a TSK-G3000SW column. The enzyme consisted of two identical subunits and the N-terminal sequence of LEP-II was determined up to the 19th residue. Although the enzyme had a broad substrate specificity it specifically hydrolyzed the peptide bonds involving the amino groups of hydrophobic amino acid residues. Various small polypeptides, such as alpha s1-CN(f1-23), alpha s1-CN(f91-100), oxidized insulin B chain, glucagon and some biologically active peptides were hydrolyzed. However, a variety of larger polypeptides or proteins, such as alpha s1-CN(f1-54), alpha s1-CN(f61-123), alpha s1-CN(f136-196), alpha s1-casein, beta-casein, and kappa-casein were not hydrolyzed. LEP-II recognized the size of its substrates, which were limited below a molecular mass of about 3.5 kDa.
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PMID:Purification and characterization of a novel metalloendopeptidase from Streptococcus cremoris H61. A metalloendopeptidase that recognizes the size of its substrate. 354 30

One way in which serum promotes survival of primary cultured hepatocytes is by inhibiting plasma membrane protease (Nakamura, T., Asami, O., Tanaka, K., and Ichihara, A. (1984) Exp. Cell Res. 155, 81-91). One of these proteases was solubilized from the plasma membranes of rat liver with 4% octyl glucoside and purified to a homogeneous state by affinity chromatography on bovine pancreatic trypsin inhibitor linked to Sepharose 4B. The protease had an apparent Mr = 120,000 by Sephacryl S-200 gel filtration and the Mr of its subunits was 30,000, as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. It appeared to be a glycoprotein. A high concentration of detergent was necessary to keep the protein soluble. The purified enzyme readily hydrolyzed synthetic tripeptide nitroanilides at sites adjacent to Arg or Lys residues, but did not degrade synthetic substrates of chymotrypsin, elastase, or aminopeptidase. It showed endopeptidase activity, hydrolyzing various proteins such as casein, hemoglobin, and denatured albumin. The enzyme was strongly inhibited by diisopropyl fluorophosphate, phenylmethanesulfonyl fluoride, bovine pancreatic trypsin inhibitor, leupeptin, antipain, and alpha 1-antitrypsin, but not by chymostatin, elastatinal, or inhibitors of carboxyl, thiol, or metallo proteases, suggesting that it is a seryl trypsin-like protease. This protease was found in plasma membranes of rat and mouse liver and in small amounts in those of kidney, but not in those of brain, red cells, Ehrlich ascites tumor, or two Morris hepatomas, suggesting that it may be involved in differentiated functions of normal hepatocytes.
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PMID:A unique trypsin-like protease associated with plasma membranes of rat liver. 394 38


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