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

It is known that the serum level of glycylproline aminopeptidase (Gly-Pro-AP) is decreased in the patients with rheumatoid arthritis. In the present study, the serum levels of various hydrolytic enzymes were tested in such patients. In comparison to the controls, many enzymes, including Ala-AP, Ser-AP, Phe-AP, Gly-Pro-AP, Gly-Pro-Leu-AP, dipeptidyl carboxypeptidase (angiotensin converting enzyme), and esterase, showed significantly decreased activities in the patients' sera. Only the activity of Trp-AP was significantly increased. Of these enzymatic activities in serum, several ones including those of Gly-Pro-AP, Ala-AP, Phe-AP, trypsin-like enzyme, and esterase, were significantly correlated with the severity of the disease. Although a part of these findings are compatible with previous observations, they suggest rather more extensive disorders of peptide metabolism in this immunological disease.
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PMID:Decreased serum levels of various hydrolytic enzymes in patients with rheumatoid arthritis. 608 27

An inhibitor(s) for post-proline cleaving enzyme was checked by using a fluorogenic substrate, Z-Gly-Pro-4-methyl coumarinamide, and was found to be distributed widely in rat and porcine organs. The highest inhibitory activity on the enzyme was observed in pancreas and the inhibitor was partially purified from porcine pancreas extract by heat treatment, chromatographies on DEAE-Sephadex and Sephadex G-50 and affinity chromatography on trypsin-Sepharose. This inhibitor was very stable against temperature, pH and trichloroacetic acid treatment. The molecular weight was estimated to be 6500 by gel filtration. This inhibitor was highly specific for prolyl endopeptidases from mammals and Flavobacterium and inhibited the enzyme competitively. It acted neither on proline specific exopeptidases such as dipeptidyl aminopeptidase IV, proline aminopeptidase, prolidase, nor usual endopeptidases such as trypsin and alpha-chymotrypsin.
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PMID:An inhibitor for post-proline cleaving enzyme; distribution and partial purification from porcine pancreas. 618 66

Pig kidney microvillar proteins were extracted with octyl beta-glucoside and reconstituted in liposomes prepared from microvillar lipids of known composition. Four peptidases, namely endopeptidase (EC 3.4.24.11), aminopeptidases N (EC 3.4.11.2) and A (EC 3.4.11.7) and dipeptidyl peptidase IV (EC 3.4.14.5), were shown to be reconstituted. At lipid/protein ratios greater than 4:1, about half the detergent-solubilized protein and nearly all of the activity of the four peptidases were reconstituted. Dissolution of the liposomes with Triton X-100 did not increase the activity of any of these peptidases, a result consistent with an asymmetric, 'right-side-out', orientation of these enzymes. When purified, endopeptidase was subjected to the same procedure; the two amphipathic forms of the enzyme (the detergent form and the trypsin-treated detergent form) were fully reconstituted. The amphiphilic form, purified after toluene/trypsin treatment, failed to reconstitute. Electron microscopy of microvilli showed that the appearance of the surface particles was profoundly altered by treatment with papain. Before treatment, the microvilli were coated with particles of stalk lengths ranging from 2.5 to 9 nm. After papain treatment nearly all the particles had stalks of 2-3 nm. Reconstituted microvillar proteins in liposomes showed the same heterogeneity of stalk length. In contrast, liposomes containing reconstituted endopeptidase revealed a very homogeneous population of particles of stalk length 2 nm. Since the smallest dimension of a papain molecule is 3.7 nm, the ability of papain, and other proteinases of similar molecular size, to release microvillar enzymes is crucially affected by the length of the junctional peptide that constitutes the stalk of this type of membrane protein.
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PMID:Proteins of the kidney microvillar membrane. Reconstitution of endopeptidase in liposomes shows that it is a short-stalked protein. 634 16

The metabolism of the cell surface glycoprotein dipeptidyl peptidase IV(DPPIV) was studied in cultured rat hepatocytes. In pulse-chase labelling experiments using L-[35S]methionine a 100-kDa high-mannose precursor polypeptide is converted into the mature complex-type 110-kDa glycoprotein. Digestion with exo- and endoglycosidases and metabolic labelling with radioactive sugars demonstrate that the 110-kDa form contains about 6 complex-type oligosaccharides which are fucosylated and sialylated. About 25 min after the beginning of the pulse-labelled glycoprotein appears in the sinusoidal membrane. Physiologically only the 110-kDa form is found in the cell surface. If cell surface DPP IV was desialylated by sialidase at 4 degrees C, it is resialylated during incubation at 37 degrees C. This oligosaccharide reprocessing indicates that the surface glycoprotein has been recycled to the cell compartment containing terminal glycosyltransferases (presumably the trans Golgi system). Two different methods demonstrate internalization of cell surface DPP IV: 1) The complex cell surface DPPIV -anti-DPP IV-antibody -L-[35S]methionine-labelled secondary goat-anti-mouse-antibody formed at 4 degrees C becomes less accessible to trypsin during incubation at 37 degrees C. 2) Part of the complex plasma membrane DPP IV-anti-DPP IV-antibody formed in the cold cannot be recognized by the radioactive secondary antibody after rewarming. Internalization is not blocked by inhibition of protein synthesis with cycloheximide. During internalization of plasma membrane DPP IV its concentration in the membrane remains constant.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Oligosaccharide reprocessing and recycling of a cell surface glycoprotein in cultured rat hepatocytes. 810 Oct 88

The steric arrangements of the amino acyl residues in the catalytic triads and tetrads of the active site are compared with each other by means of systematic analysis of the conformation of the serine proteases stored in the Brookhaven Protein Data Bank. On this basis a differentiation between the representatives of the (chymo)trypsin family on the one hand and those of the subtilisin family on the other hand is found. The enzyme tonin distinguishes from representatives of the (chymo)trypsin family and should be classified to a new subclass of this family. Thermitase represents a new subclass of the subtilisins. The spatial orientation of the amino acyl residues of the active site of tonin suggests a new mechanism of enzyme catalysis that possibly also occurs in dipeptidyl peptidase IV.
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PMID:Classification of serine proteases derived from steric comparisons of their active sites. 814 70

A comparative study of proteolytic enzymes and their inhibitors in three human leukemic lymphoid cell populations has been carried out. The lysates of all lymphoid cells contained cathepsins D, B, L and H as well as serine trypsin-like proteinases, several aminopeptidases, dipeptidyl aminopeptidase IV and plasminogen activator (urokinase type). The activities of individual proteinases and their ratios in all cell types under study varied essentially, suggesting that lymphoid cells with different functions have different sets of proteolytic enzymes. FPLC chromatography of the lysates revealed the presence of inhibitors of cysteine and serine trypsin-like proteinases. The procedure for isolation of cathepsins D, B, L and H and of their inhibitors has been proposed and partially purified protein preparations obtained. Some properties of cathepsins B and L and those of their inhibitor have been examined.
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PMID:[Proteolytic enzymes in human lymphocytic leukemia cells. II. Comparative characteristics of proteolytic enzymes and their inhibitors in three differing types of lymphoid cells]. 836 26

A number of dipeptide diphenyl phosphonate esters were studied as inhibitors of dipeptidyl peptidase IV, focusing on the role of the P2 residue in the inactivation process. The active compounds were slow irreversible inhibitors of the catalytic activity of the enzyme. With proline (or alanine) in the P1 position, the rate constants of inactivation correlated with the acylation rate constants reported for homologous dipeptide derived substrates. The kinetic data indicate that the mechanism of inhibition consists of the formation of a fairly weak initial complex, followed by a slow irreversible inactivation step. This indicates that, as in the case of trypsin-like proteinases, dipeptide diphenyl phosphonate esters form a covalent adduct with the catalytic site of DPP IV, even though this enzyme belongs to a completely distinct class of serine peptidases. Enantioselectivity and secondary specificity further support the evidence that diphenyl phosphonate esters are mechanism-based inhibitors. The dipeptide diphenyl phosphonate esters had a half-life of 3-10 h at 37 degrees C in Tris buffer. The inhibitors were degraded in human plasma, depending on the type of amino-terminal amino acid. The compound with proline in the P2 position was the most resistant to degradation in plasma. Due to their stability and the irreversible nature of the inhibition, the diphenyl phosphonate esters promise to be useful tools in the continuing investigation of the physiological function of dipeptidyl peptidase IV.
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PMID:Dipeptide-derived diphenyl phosphonate esters: mechanism-based inhibitors of dipeptidyl peptidase IV. 864 10

The T-cell activation antigen CD26, is a type II membrane glycoprotein with intrinsic dipeptidyl-peptidase IV (DPP IV) activity, characterized by its capacity to cleave off N-terminal dipeptides containing proline as the penultimate residue. Independent of its catalytic activity, CD26 has also been characterized as adenosine deaminase binding protein. By using CD26 negative human C8166 cells, here we describe the existence of another cell-surface protein which manifests CD26-like DPP IV activity. For convenience, this protein will be referred to as DPP IV-beta. Consistent with the cell-surface expression of DPP IV-beta, intact C8166 cells manifested a high level of DPP IV, whereas, they manifested poor activity against substrates of DPP II known to have an intracellular localization. A partially purified preparation of CD26 from human MOLT4 cells, and the DPP IV-beta expressed on intact cells were found to possess similar catalytic activity and pH optimum. In addition, cell-surface CD26 and DPP IV-beta on intact MOLT4 and C8166 cells, respectively, resisted digestion by proteolytic enzymes such as trypsin and proteinase K. However, adenosine deaminase activity was not detectable on the surface of C8166 cells in contrast to CD26 positive MOLT4 cells. In accord with this, 125I-labeled adenosine deaminase which binds CD26 was found not to bind DPP IV-beta. Gel-filtration experiments using 0.5% Triton X-100 extracts from C8166 and MOLT4 cells, revealed that the apparent molecular mass of DPP IV-beta is 82 kDa, whereas that of CD26 is 110 kDa as expected. Taken together, our results suggest that DPP IV-beta is a CD26-like protein which could be characterized by distinct properties.
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PMID:Dipeptidyl-peptidase IV-beta, a novel form of cell-surface-expressed protein with dipeptidyl-peptidase IV activity. 870 27

By comparison of the cell surface proteins derived from the outer membrane and fibrils from 14 Prevotella intermedia and 19 Prevotella nigrescens strains using SDS and analysed by SDS-PAGE, it was possible to distinguish the two species. A polypeptide of approx. 21 kDa distinguished P. intermedia strains, whereas two polypeptides of approx. 18 and 22 kDa could be used to identify P. nigrescens strains. Four other human oral black pigmented bacterial species (Porphyromonas gingivalis, Prevotella denticola, Prevotella loescheii and Prevotella melaninogenica) did not have the 18-, 21- or 22-kDa polypeptides shown by P. intermedia or P. nigrescens. The cell-associated proteolytic activity of eight strains of P. intermedia, 14 strains of P. nigrescens and one strain of P. gingivalis (W50) was assessed using four chromogenic substrates. The hydrolysis of the substrate GPPNA (indicative of dipeptidyl peptidase IV-like activity) and SAAPPNA (elastase-like activity) by P. intermedia strains varied from 32 to 114 units and 0.5 to 12.6 units of activity respectively, where one unit was defined as the amount of protease enzyme catalysing the formation of 1 nmol of p-nitroaniline under experimental conditions. 37.5% (3 of 8) of P. intermedia strains hydrolysed SAAPPNA (chymotrypsin-like enzyme activity) with activities of between 7 and 12 units. The hydrolysis of GPPNA and SAAAPNA by P. nigrescens strains was 32-149 and 3-16 units, respectively. 57% (8 of 14) of P. nigrescens strains hydrolysed SAAPPPNA with activities ranging from 3 to 8 units. None of the P. intermedia or P. nigrescens strains examined were found to have trypsin-like enzyme activity (BAPNA hydrolysis). The GPPNA and SAAAPNA hydrolytic activity associated with the proteases from Porphyromonas gingivalis W50 was at least twice that of P. intermedia and P. nigrescens strains. The similar peptidase activities of P. intermedia and P. nigrescens against chromogenic substrates cannot be used to differentiate the species, but SDS-PAGE of cell surface protein extracts allowed unambiguous speciation between P. intermedia and P. nigrescens. This simple technique of cell surface protein analysis can be performed in most laboratories and offers a convenient way by which to differentiate the two species.
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PMID:An investigation into the use of SDS-PAGE of cell surface extracts and proteolytic activity to differentiate Prevotella nigrescens and Prevotella intermedia. 886 94

Gingival crevicular fluid (GCF) was collected from chronic periodontitis patients using plastic micropipettes and coverslip smears stained with antibodies for leukocyte markers and Toluidine Blue for mast cells. The smears consisted of 70-80% granulocytes, 10-20% monocytes/macrophages, 5% mast cells and 5% T lymphocytes; no B lymphocytes were found. Proteases and inhibitors in GCF cells were investigated by enzyme cytochemistry using 2-methoxy-4-naphthylamine-linked peptide substrates and simultaneous coupling to Fast Blue B and immunocytochemistry using biotinylated secondary antibodies and an alkaline phosphatase/new fuchsin detecting system. Elastase was detected in granulocytes, cathepsin B in macrophages, dipeptidyl peptidases II and IV in a small proportion of macrophages, dipeptidyl peptidase IV in a few T lymphocytes, tryptase in mast cells and alpha-1-proteinase inhibitor and alpha-2-macroglobulin in some macrophages. GCF was also collected on filter paper strips and eluted into buffer for biochemical enzyme assays. Lysis of cells by addition of detergent to the elution buffer increased activities to 140-240% of control values. Removal of cells by centrifugation reduced measured activities to 1-30% of original figures; this effect was less if samples were pre-treated with detergent. Proteases from inflammatory cells therefore appear to make up most of the measured enzyme activity in GCF, and this association may explain recent correlations with periodontal disease progression.
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PMID:Investigations into the cellular contribution to host tissue proteases and inhibitors in gingival crevicular fluid. 920 22


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