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)

Bound sialic acids on rat spermatozoa were assayed by oxidation with 1 mM-NaIO4 at 0 degree C, liberating C-9 as formaldehyde which was further quantitated using 3-methyl-2-benzothiazolinone. The mean +/- s.d. (n = 20) content of bound sialic acids of spermatozoa from the caput and cauda epididymidis was 50.9 +/- 8.0 and 25.2 +/- 3.8 nmol/10(8) spermatozoa respectively. About 85% of the former and 75% of the latter could be extracted by 1% Triton X-100 and 2 mM-dithiothreitol. About 70% of the former and 20% of the latter were released by neuraminidase from Vibrio cholerae. About 40% of the former and 30% of the latter were sensitive to trypsin. During sperm maturation, the decrease in the total bound sialic acids was due to the decrease in the neuraminidase-sensitive but not the neuraminidase-resistant sialic acids.
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PMID:Direct assay of bound sialic acids on rat spermatozoa from the caput and cauda epididymidis. 630 Mar 82

We describe a method for synchronously assembling antigen-antibody complexes underneath macrophages adherent to an antigen-coated surface. We have used this method to study the mechanism of Fc receptor (FcR) disappearance that occurs when resident and thioglycollate-elicited mouse macrophages are cultured on immune complex-coated surfaces. Erythrocytes opsonized with IgG (E(IgG) and a monoclonal antibody (2.4G2 IgG) directed against the trypsin-resistant FcR (FcRII) were used as indicators of the presence and distribution of FcRII molecules on the macrophage plasma membrane. Inhibitors of aerobic (NaCN) and anerobic (2-deoxyglucose, NaF) glycolysis and pinocytosis, of protein biosynthesis (cycloheximide), and of cytoskeletal function (cytochalasin B and D, colchicine, podophyllotoxin, taxol) did not reduce the rate or extent of FcRII modulation. Moreover, treatment of the macrophages with 0.1-0.5% formaldehyde did not reduce the extent of FcRII modulation as measured by the disappearance of E(IgG) binding sites. FcRII modulation was markedly slowed when the temperature was decreased to 2-4 degrees C. These results prove that FcRII modulation is governed by diffusion of the receptor in the plasma membrane. From the speed of FcRII disappearance from the macrophage's upper surface we calculate that the receptor has a diffusion coefficient at 37 degrees C of 2.5 X 10(-9) cm2/s. This finding indicates that FcRII, in its unligated form, is not linked to the macrophage's cytoskeleton, and that the receptor is capable of accommodating spatially to any distribution of ligands on a particle's surface.
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PMID:Fc receptor modulation in mononuclear phagocytes maintained on immobilized immune complexes occurs by diffusion of the receptor molecule. 634 50

The occurrence and characteristics of hemagglutinins were investigated in 310 Klebsiella strains (195 K. pneumoniae- and 115 K. oxytoca-strains). Mannose-sensitive (MS)-hemagglutinins as well as Mannose-resistant (MR/K)-hemagglutinins could be demonstrated, only 13 Klebsiella-strains were not able to hemagglutinate. MS-hemagglutinins were much more often found in K. pneumoniae- than in K. oxytoca-strains, whereas the MR/K-hemagglutinin-frequency was equally high. Features (resistance to formaldehyde, trypsin, pronase, glycosidases, sodium metaperiodate and heating) and pathogenic significance of these hemagglutinins (fimbriae) were discussed.
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PMID:Hemagglutinins of Klebsiella pneumoniae and Klebsiella oxytoca. 636 75

A peptide from sperm whale myoglobin, residues 132-153, and a chromogenic substrate, H-D-valyl-L-leucyl-L-lysyl-p-nitroanilide diacetate, were selected to investigate the susceptibility of peptide bonds adjacent to N epsilon,N-dimethyllysyl residues to tryptic hydrolysis. The peptides were exhaustively methylated using formaldehyde and sodium cyanoborohydride (N. Jentoft and D. G. Dearborn (1979) J. Biol. Chem. 254, 4359-4365). Unmodified and methylated peptides were digested with trypsin or submaxillary protease, an enzyme that catalyzes the hydrolysis of only arginyl bonds in proteins. Trypsin catalyzed the hydrolysis of the methylated apomyoglobin peptide only at the single arginyl residue and not at any of the four N epsilon,N-dimethyllysyl residues. Trypsin also failed to catalyze the hydrolysis of reductively methylated H-D-valyl-L-leucyl-L-lysyl-p-nitroanilide. Even a 17-fold molar excess of the methylated substrate did not appear to alter the rate of tryptic hydrolysis of the unmodified substrate. These results are discussed with regard to the interactions of substrates within the specificity site of trypsin.
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PMID:The resistance to tryptic hydrolysis of peptide bonds adjacent to N epsilon,N-dimethyllysyl residues. 640 26

The possibility of preservation and restoration of antigenicity of some antigens in paraffin-embedded tissue was evaluated by direct immunofluorescent technique on deparaffinized sections. Fixation with 96% ethanol-1% acetic acid, 10% neutral buffered formalin and p-formaldehyde was useful for the preservation of tissue antigens and immune deposits, whose antigenicity could be easily restored by trypsin digestion. Neutral buffered formalin was also a satisfactory fixative in immunofluorescent staining on lymphocyte/plasma cell-bound immunoglobulins. Fixation with alcohol-Bouin's fluid showed contrast results; feasible for staining of cell-bound immunoglobulins, but poor for that of glomerular immune deposits. After papain digestion, BSA and lysozyme, antigens of immune complexes, were easily detected in experimental chronic serum sickness glomerulonephritis. Pepsin was more efficient than trypsin in restoring the antigenicity of renal tissue antigens such as fibronectin and polyantigenic basement membrane, but the brush border antigen of the proximal renal tubules was frail to the pepsin digestion. In general, the enzymatic digestion time necessary for the restoration of antigenicity was in parallel with fixation time. Results obtained have shown that deparaffinized sections could be used as satisfactory substrate for immunohistochemistry when proper fixation and efficient proteolytic enzymatic pretreatments were performed.
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PMID:Restoration of antigenicity of tissue antigens, cell-bound immunoglobulins and immune deposits in paraffin-embedded tissue. The influence of fixation and proteolytic enzymatic digestion. 643 48

Lipoprotein lipase mediated transfer of cholesteryl ester and its ether analog, cholesteryl linoleyl ether, from unilamellar liposomes, prepared from a nonhydrolyzable ether analog of 1,2-diacyl-sn-glycero-3-phosphocholine (PC), 1,2-dioleyl ether-sn-glycero-3-phosphocholine (DOEPC), was studied in various cells in culture. It was found that lipoprotein lipase enhanced the uptake of cholesteryl linoleyl ether and of DOEPC. These findings provided a definitive proof that hydrolysis of liposomal PC is not needed for the lipoprotein lipase catalyzed transfer of cholesteryl linoleyl ether and cholesteryl ester to cells. The lipids transferred by lipoprotein lipase to cells were localized in three compartments, trypsin-releasable, resistant and metabolic; the latter was a chloroquine-sensitive pool as evidenced by inhibition of cholesteryl ester hydrolysis. Labeled PC and, to a lesser extent DOEPC, in the trypsin-releasable pool was able to return to the medium, while cholesteryl linoleyl ether and cholesteryl ester required cholesteryl ester transfer protein for release. The transfer of cholesteryl linoleyl ether and cholesteryl ester into a trypsin-resistant compartment did not require metabolic energy and occurred also in formaldehyde-fixed cells. Metabolic energy was needed for the translocation of cholesteryl linoleyl ether and cholesteryl ester into the lysosomal compartment, presumably by a process of endocytosis. The physiological relevance of the present findings is that as intravascular hydrolysis of triacylglycerol-rich lipoproteins is mediated by lipoprotein lipase attached to endothelial cells, the latter can provide a very extensive surface for removal and metabolism of phospholipids and cholesteryl ester by a mechanism mediated by lipoprotein lipase.
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PMID:Lipoprotein lipase mediated uptake of non-degradable ether analogues of phosphatidylcholine and cholesteryl ester by cultured cells. 646 98

Somatic neurohybrid SB21B1 cells grown in serum exhibit limited capacity to bind 125I-labeled tetanus toxin and cannot synthesize gangliosides higher than GM2. By 6 h after supplementing the culture medium with pure or mixtures of brain gangliosides, binding of 125I-labeled tetanus toxin to cells increases approximately 8-fold compared to that of nonsupplemented cells. The uptake of added gangliosides is a saturable process and is facilitated by serum removal (2.1-fold) or substitution of growth factors for serum (3.8-fold). Enhancement of tetanus toxin binding to cells depends on the ganglioside species and concentration; GT1b (25 micrograms/ml) is, respectively, two and three times as effective as GD1b and GM1 in increasing toxin binding. Reconstitution of ganglioside-mediated tetanus toxin binding activity is a reversible phenomenon; removal of medium gangliosides causes a 3-fold drop in toxin binding by 24 h, after which an apparent plateau for at least 3 days above the basal level is established. As in cerebral cultures, binding of toxin to ganglioside-supplemented neurohybrid cells exhibits salt and sialidase sensitivity and is enhanced 2.6-fold at 37 degrees C compared to 0-4 degrees C. The resultant temperature-dependent toxin-cell association is sialidase insensitive. Fixation of cells by formaldehyde or treatment of ganglioside-supplemented cells with trypsin has no substantial effect on ganglioside-mediated binding of the toxin. Methanol/chloroform treatment of cells causes a 91.4% loss of binding activity.
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PMID:Gangliosides mediate association of tetanus toxin with neural cells in culture. 671 26

The fate of s.c. implants of fibrous, trypsin-purified human dermal collagen and collagen cross-linked with formaldehyde and glutaraldehyde has been studied in rats. Dermal collagen, and untreated skin implants, underwent resorption associated with a pronounced round-cell reaction. While collagen implants cross-linked with solutions of 0.04% and 0.08% formaldehyde became reduced in size, those cross-linked with 1% formaldehyde and 0.01%, 0.02% and 0.04% glutaraldehyde, although undergoing some collagen remodelling, retained their original size over the 25-week period of study. At 5 weeks the aldehyde cross-linked implants showed their greatest cellularity, reaching a lower, more stable cell population by 18 weeks. More round cells were seen at 5 weeks, particularly after formaldehyde cross-linking, than a later times when few were present. The results indicate that aldehyde-stabilized preparations of heterograft dermal collagen could have applications in the repair of tissue defects in man.
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PMID:Effect of aldehyde cross-linking on human dermal collagen implants in the rat. 677 96

Receptors for C3b (C3R) in human spleen and kidney were studied using haemadsorption to cryostat sections. The indicator cells, ovine erythrocytes (E) coated with rabbit IgM antibody (A) and human C3b (EAC) adhered strongly to the glomeruli in renal tissue and to the white pulp of spleen. Titration experiments showed that avidity of the two populations of C3R was equal. Activity was independent of Ca++ and Mg++. Periodic acid, formaldehyde, high salt concentrations and trypsin abolished, whereas neuraminidase enhanced the activity. Various temperatures and pHs affected the two populations of C3R similarly. The results obtained indicate that the C3R in spleen and kidney are similar.
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PMID:Similarities of C3b receptors in human kidney and spleen. 679 Apr 44

Using trypsin-purified rat dermal collagen labelled with tritiated hydroxyproline and proline, a study has been made of hydroxyproline turnover in non-cross-linked and glutaraldehyde- and formaldehyde-cross-linked collagen when implanted s.c. in unlabelled isogenic rats. Grafts cross-linked with 0.01% glutaraldehyde maintained their collagen mass over a 22-week period, loss of original collagen being balanced by the gain in new collagen (22% at 22 weeks). Cross-linking with 5% formaldehyde temporarily inhibited collagen loss as compared with non-cross-linked grafts. However, at 22 weeks both had lost some 30% of their collagen mass, the gain of new collagen (some 8%) only partially compensating for the loss of original implant collagen.
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PMID:3H-collagen turnover in non-cross-linked and aldehyde-cross-linked dermal collagen grafts. 680 62


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