Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transformation of the chick fibroblast surface has been studied in cells infected with Schmidt-Ruppin Rous sarcoma virus and the temperature-sensitive mutant of this virus, TS-68. Major findings following transformation induced by a shift from nonpermissive (41 C.) to permissive (36 C.) temperature in TS-68 infected cells were: (1) rapid cessation or slowing of the synthesis of a protein, M.W. 100-200,000, localization uncertain; (2) cessation or slowing of the synthesis of a plasma membrane protein, M.W. 45,000, within 2-4 hours; (3) cessation or slowing of the synthesis of a large trypsin- and collagenase- sensitive protein (M.W. greater than 200,000) only after an extended period of morphologic transformation. In addition, increased quantities of type-specific viral antigen in the membranes of infected cells were observed in TS-68-infected cells at 41 compared with 36 C.
 ...
PMID:Comparisons of major cell-surface proteins of normal and transformed cells. 16 7

Preparations yielding a high percentage of undamaged axons from fresh peripheral nerve or nerve root were made using an enzymatic dissociation regimen. The nerve was placed in a temperature-controlled chamber mounted over an inverted phase-contrast microscope. An oxygenated solution (Brimijoins) or modified Hank's solution was pumped through the chamber, first in a calcium-free form and then containing enzymes. The enzymes for dissociation were collagenase and trypsin, alternated. Enzymatic dissociation of the epineurium, perineurium and extracellular matrix was achieved. We supplemented the gentle agitation of a 10-roller peristaltic pump by periodically raising and lowering the fluid level in the chamber to provide a controlled mechanical agitation that promoted dissociation. A large percentage of the axons can be dissociated from the nerve, varying from approximately one-quarter to occasional complete dissociation. Action potentials were still conducted through dissociated axons, and axon transport was also still present, as documented by direct visualization using an AVEC-DIC type of microscope system. The axons had a better morphological appearance and displayed better transport than comparison preparations prepared by the usual mechanical teasing method, in our hands. The enzymatic method allows study of axons in an adult or developing mammal with regard to their electrical conduction and axon transport mechanisms. It should help to avoid a selection process for more hardy axons which may be imposed by traditional mechanical teasing methods. Mechanical stress was observed to cause widened Schmidt-Lanterman clefts, widened nodes, myelin bubbles, and other abnormal morphology as evidence of damage.
 ...
PMID:A method for in vitro enzymatic dissociation of nerve roots and peripheral nerves from adult mammals. 241 9

The penetration and distribution of ruthenium red in the axon-myelin-Schwann cell complex of developing rabbit peripheral nerve fibers are investigated. Ruthenium red positive material is established in the axoplasm, axolemma, periaxonal space, major dense lines and intraperiod lines of the compact myelin, mesaxons, split peripheral myelin lamellae, Schmidt-Lanterman and longitudinal incisures, paranodal loops and axo-glial contacts, Schwann cell cytoplasm and basal lamina, nodal extracellular matrix, desmosome-like structures, endoneural collagen. Some features of the distribution of the contrast material in the developing myelin sheath are described. Regional differences of the axolemma and of the Schwann cell cytoplasm and plasmalemma are established. The prevalence of glycoproteins or glycolipids in the ruthenium red stained material in its different localizations is discussed on the basis of trypsin and hyaluronidase digestion performed.
 ...
PMID:Localizations of ruthenium red positive material in rabbit peripheral nerves. 242 14

The amino acid sequence of staphylococcal enterotoxin A is presented. Staphylococcal enterotoxin A is a single-chain polypeptide which consists of 233 amino acid residues with a molecular weight of 27,078 and has the amino acid composition Cys2, Asp17, Asn19, Thr16, Ser13, Glu15, Gln12, Pro4, Gly15, Ala7, Val13, Met2, Ile10, Leu23, Tyr18, Phe8, His6, Lys24, Arg7, Trp2, with serine as both amino- and carboxyl-terminal amino acids. Automated sequence analysis of intact enterotoxin A, as well as characterization of the peptides obtained from cyanogen bromide treatment and trypsin and chymotrypsin digestion, led to the elucidation of the complete primary structure of this protein. Less structural homology is observed among staphylococcal enterotoxins A, B (Huang, I-Y., and Bergdoll, M. S. (1970) J. Biol. Chem. 245, 3518-3525), and C1 (Schmidt, J. J., and Spero, L. (1983) J. Biol. Chem. 258, 6300-6306) than that seen between enterotoxins B and C1.
 ...
PMID:Complete amino acid sequence of staphylococcal enterotoxin A. 358 6

Bovine pancreatic ribonuclease (RNase) A and S protein (enzymatically inactive proteolytic fragment of RNase A which contains RNA binding site) stimulate the activation, as evidenced by increasing DNA-cellulose binding, of highly purified rat hepatic glucocorticoid-receptor complexes. These effects are dose dependent with maximal stimulation of DNA-cellulose binding being detected at approximately 500 micrograms (50 units of RNase A/mL). RNase A and S protein do not enhance DNA-cellulose binding via their ability to interact directly with DNA or to increase nonspecific binding of receptors to cellulose. Neither S peptide (enzymatically inactive proteolytic fragment which lacks RNA binding site) nor cytochrome c, a nonspecific basic DNA binding protein, mimics these effects. RNase A and S protein do not stimulate the conformational change which is associated with activation and is reflected in a shift in the elution profile of receptor complexes from DEAE-cellulose. In contrast, these two proteins interact with previously heat-activated receptor complexes to further enhance their DNA-cellulose binding capacity and thus mimic the effects of an endogenous heat-stable cytoplasmic protein(s) which also function(s) during step 2 of in vitro activation [Schmidt, T. J., Miller-Diener, A., Webb, M. L., & Litwack, G. (1985) J. Biol. Chem. 260, 16255-16262]. Preadsorption of RNase A and S protein to an RNase affinity resin containing an inhibitory RNA analogue, or trypsin digestion of the RNA binding site within S protein, eliminates the subsequent ability of these two proteins to stimulate DNA-cellulose binding of the purified receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Effects of bovine pancreatic ribonuclease A, S protein, and S peptide on activation of purified rat hepatic glucocorticoid-receptor complexes. 379 Apr 97

Clostridium botulinum type E neurotoxin, a single-chain protein of Mr 147,000, was purified and subjected to amino acid sequencing. The same was done for single-chain botulinum type B neurotoxin (Mr 152,000), and for the heavy and light chains (Mr 104,000 and 51,000 respectively) derived from type B by limited trypsin digestion. Twelve to eighteen residues were identified and the following conclusions were drawn: The light chain of the nicked (dichain) type B is derived from the N-terminal one-third of the single-chain (unnicked) parent neurotoxin; sequence homologies are present between single-chain types B and E and the light chain of the nicked type A [J. J. Schmidt, V. Sathyamoorthy, and B. R. DasGupta (1984) Biochem. Biophys. Res. Commun. 119, 900-904]; the N-terminal regions of the heavy chains of types A and B have some structural similarity; and activation of type B neurotoxin cannot involve removal of amino acids or peptides from the N terminus.
 ...
PMID:Partial amino acid sequences of botulinum neurotoxins types B and E. 388 13

Thermal "activation" or "transformation" of rat hepatic [6,7-3H]triamcinolone acetonide (TA)-receptor complexes purified in the unactivated state to near homogeneity (Grandics, P., Miller, A., Schmidt, T. J., Mittman, D., and Litwack, G. (1984) J. Biol. Chem. 259, 3173-3180) has been further investigated. The data generated in reconstitution experiments demonstrate that warming (25 degrees C for 30 min) of the purified unactivated complexes promotes their activation as judged by an increase in DNA-cellulose binding, but to a lower extent than that observed after warming of glucocorticoid-receptor complexes in crude cytosols. However, maximal DNA-cellulose binding capacity can be detected in reconstituted systems (also heated at 25 degrees C for 30 min) consisting of purified unactivated [3H]TA-receptor complexes and a cytoplasmic "stimulator(s)." This cytoplasmic factor(s), which does not copurify with the receptor, is heat-stable (90 degrees C for 30 min), excluded from Sephadex G-25, and trypsin-sensitive and stimulates DNA-cellulose binding in a dose-dependent manner. The ability of Na2MoO4 to block thermal activation of the highly purified receptor complexes suggests that this transition metal anion interacts directly with the receptor protein itself. The fact that the cytoplasmic stimulator(s) enhances DNA-cellulose binding of the [3H]TA-receptor complexes without increasing the proportion of those complexes eluted in the activated (low salt) position from DEAE-cellulose is consistent with a proposed two-step model of in vitro activation. During the Na2MoO4-sensitive Step 1, elevated temperature (25 degrees C for 30 min) may directly alter the conformation of the purified receptor complexes (i.e. subunit dissociation or disaggregation), resulting in the appropriate shift in the elution profile of the [3H]TA-receptor complexes on DEAE-cellulose but only in a minimal (approximately 2-3-fold) increase in the binding of these complexes to DNA-cellulose. During the Na2MoO4-insensitive and temperature-independent Step 2, a heat-stable cytoplasmic protein(s) may interact with these thermally activated [3H]TA-receptor complexes and enhance their ability to bind to DNA-cellulose without further increasing the percentage of those complexes which elute from DEAE-cellulose in the activated position. In crude cytosols these two steps would presumably occur simultaneously, and addition of Na2MoO4 prior to warming would block Step 1 and hence Step 2 would not occur.
 ...
PMID:Thermal activation of the purified rat hepatic glucocorticoid receptor. Evidence for a two-step mechanism. 406 9

Brain capillary endothelium in vivo contains high levels of gamma-glutamyltranspeptidase activity. In addition, the presence of this enzyme has been used as a marker of neoplastic cells. Normal rat cerebral endothelial cells in culture exhibit a specific activity for gamma-glutamyltranspeptidase of 2 units/10(6) cells. In vitro transformation of these cells is achieved by the use of an avian retrovirus, Schmidt-Ruppin RSV-strain D. The resultant cell line, designated RCE-T1, demonstrates a significant increase in gamma-glutamyltranspeptidase activity up to 20 units/10(6) cells in early passage levels (9-26) after which enzyme activity declines and returns to normal levels by passage 80. This variation in enzyme activity correlates with histochemical staining for this enzyme. Furthermore, the enzyme activity increases linearly over a 1000-fold range of cell concentrations. Various culture modifications do not influence this pattern of enzyme expression. These parameters include trypsin dissociation, cell freezing, degree of confluency and culture maintenance with serum or with conditioned medium obtained from passage levels exhibiting high or low enzyme activity. RCE-T1 cells will provide a unique model system to study the distribution and regulation of this enzyme during differentiation and viral carcinogenesis.
 ...
PMID:Expression of gamma-glutamyltranspeptidase in a transformed rat cerebral endothelial cell line. 614 9

The family of WD-repeat proteins comprises over 30 different proteins that share a highly conserved repeating motif [Neer, E. J., Schmidt, C. J., Nambudripad, R., & Smith, T. F. (1994) Nature 371, 297-300]. Members of this family include the signal-transducing G protein beta subunit, as well as other proteins that regulate signal transduction, transcription, pre-mRNA splicing, cytoskeletal organization, and vesicular fusion. The crystal structure of one WD-repeat protein (G beta) has now been solved (Wall et al., 1995; Sondek et al, 1996) and reveals that the seven repeating units form a circular, propeller-like structure with seven blades each made up of four beta strands. It is very likely that all WD-repeat proteins form a similar structure. If so, it will be possible to use information about important surface regions of one family member to predict properties of another. If WD proteins form structures similar to G beta, their hydrodynamic properties should be those of compact, globular proteins, and they should be resistant to cleavage by trypsin. However, the only studied example of a WD-repeat protein, G beta, synthesized in vitro in a rabbit reticulocyte lysate, is unable to fold into a native structure without its partner protein G gamma. The non-WD-repeat amino terminal alpha helix of G beta does not inhibit folding because G beta does not fold even when this region is removed. It is not known whether all WD-repeat proteins are unable to fold when synthesized in an in vitro system. We synthesized seven members of the family in a rabbit reticulocyte lysate, determined their Stokes radius, sedimentation coefficient, and frictional ratio, and assayed their stability to trypsin. Our working definition of folding was that the proteins from globular, trypsin-resistant structures because, except for G beta gamma, their functions are not known or cannot be assayed in reticulocyte lysates. We chose proteins that include amino and carboxyl extensions as well as proteins that are made up entirely of WD-repeats. We show that unlike G beta, several proteins with WD-repeats are able to fold into globular proteins in a rabbit reticulocyte lysate. One protein, beta Trcp, formed large aggregates like G beta, suggesting that it may also require a partner protein. Despite the presence of many potential tryptic cleavage sites, all of the proteins that did fold gave stable large products on tryptic proteolysis, as predicted on the basis of the structure of G beta. These studies suggest that other WD-repeat proteins are likely to form propeller structures similar to G beta.
 ...
PMID:Folding of proteins with WD-repeats: comparison of six members of the WD-repeat superfamily to the G protein beta subunit. 890 96

Although the mesquite plant (Prosopis velutina) is not as widely distributed as some other allergenic species, its pollen can induce serious pollinosis in areas where it is localized. We previously isolated and characterized a peptidase from mesquite pollen with trypsin-like specificity (peptidase Imes) (Matheson, N., Schmidt, J., and Travis, J. (1995) Am. J. Respir. Cell Mol. Biol. 12, 441-448). Now we have characterized a second enzyme with specificity for hydrophobic residues (mesquite pollen peptidase IImes). This enzyme has a molecular mass near 92 kDa and activity that was not affected by reducing or chelating agents but was inhibited by specific synthetic serine proteinase inhibitors and the aminopeptidase inhibitor bestatin. However, it was not inhibited by human plasma proteinase inhibitors, nor did it inactivate any of those tested. The enzyme possessed amidolytic activity against p-nitroanilide substrates most effectively after alanine residues and also displayed aminopeptidase activity against non-p-nitroanilide peptides with a preference for phenylalanine. This specificity for hydrophobic amino acid residues was corroborated by inhibition studies with chloromethyl ketone and organophosphonate inhibitors. More interesting from a physiological point of view is that the bioactive peptides, angiotensins I and II and vasoactive intestinal peptide, were also hydrolyzed rapidly, indicating an ability of peptidase IImes to act also as an oligopeptidase. Because these bioactive peptides play a role in the inflammatory responses in allergic asthma, our data suggest that the purified mesquite pollen peptidase IImes may be involved in the degradation of neuro- and vasoactive peptides during pollen-initiated allergic reactions.
 ...
PMID:Purification and characterization of a novel peptidase (IImes) from mesquite (Prosopis velutina) pollen. 964 33


1 2 Next >>