Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It was reported previously that radiation-induced cytotoxicity in V79A03 (V79) cells was attenuated by pretreatment of cells with leukotriene C4 (LTC4), leading us to determine that V79 cells possessed specific binding sites, with characteristics of receptors, for LTC4 (see the preceding, companion communication). Additional studies were conducted to determine the subcellular distribution and the chemical nature of the LTC4 binding site in V79 cells. Trypsin treatment of cells before LTC4 binding assays resulted in a 74% reduction in high-affinity binding. In tests to examine the subcellular location of LTC4 binding, plasma membrane and nuclear fractions were obtained from V79 cells. In contrast to Scatchard analyses of LTC4 binding to intact cells which were curvilinear, Scatchard analyses of nuclear and plasma membrane fractions were linear, indicative of the presence in these cellular substituents of low and high-affinity binding, respectively. To examine the nature of the high-affinity LTC4 binding sites, intact V79 cells were photolyzed with [3H]-LTC4 rendered photoactive by preincubation with N-hydroxysuccinimidyl-4-azidobenzoate. The cell-bound radioactivity migrated during sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with an apparent molecular weight of approximately 40 kdal. Five different commercial preparations of glutathione-S-transferase (GST), which has been implicated as a source of LTC4 "specific binding" in other cells, migrated in the same SDS-PAGE system with an apparent molecular weight of 20-24 kdal. Furthermore, preincubations of V79 cells with three antisera generated against GST had minimal effects upon subsequent LTC4 binding to intact cells. These data, taken together with the data from the preceding companion communication, suggest that the radioprotective effect of LTC4 upon V79 cells may be attributable to a receptor-mediated phenomenon which appears distinct from leukotriene binding to GST.
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PMID:Interaction of leukotriene C4 and Chinese hamster lung fibroblasts (V79A03 cells). 2. Subcellular distribution of binding and unlikely role of glutathione-S-transferase. 228 Nov 44

1. NADH-cytochrome b5 reductase was purified from sheep lung microsomes in the presence of non-ionic and ionic detergents, Emulgen 913 and cholate, respectively. 2. The purification procedure involved the ion-exchange chromatography of the detergent solubilized microsomes on DEAE-cellulose. 3. Further purification and concentration of lung reductase was carried out with a second DEAE-cellulose column followed by the affinity column chromatography of partially purified reductase on 5'-ADP-agarose column. 4. The specific activity of sheep lung reductase was 638 mumol ferricyanide reduced/min/mg protein and the yield was 6% of the initial activity in microsomes. 5. The SDS-polyacrylamide gel electrophoresis of the purified lung reductase showed one protein band having the monomer mol. wt of 34,500 +/- 1500. In the presence of 0.4% deoxycholate, it existed as an active dimer having a mol. wt of 68,500. 6. Trypsin treated lung reductase showed two extra protein bands of mol. wts of 28,000 and 25,000 on 10% SDS-polyacrylamide gels. 7. The purified enzyme was found to contain FAD as prosthetic group and the absorption spectrum of lung reductase showed two peaks at 390 and 461 nm which were typical for flavoproteins and a shoulder at 490 nm. 8. The maximal activity of lung reductase was observed between pH 6.5-8.0 and at pH 6.8, when ferricyanide and partially purified sheep lung cytochrome b5 was used as electron acceptors, respectively.
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PMID:Purification of NADH-cytochrome b5 reductase from sheep lung and its electrophoretic, spectral and some other properties. 228 61

ATP:citrate lyase was purified from the oleaginous yeast Rhodotorula gracilis to homogeneity as judged by polyacrylamide gel electrophoresis, using a novel citrate-Sepharose procedure. The enzyme was found to have a molecular weight of 520,000 and consisted of four identical subunits (Mr = 120,000). Two minor low molecular weight bands were observed on SDS-PAGE (Mr 51,000 and 49,000). Trypsin digestion experiments indicated that these could have been the result of limited proteolysis by an endogenous trypsin-like proteinase. In this respect, it resembles the mammalian ATP:citrate lyase. The enzyme was stimulated by NH+4 ions and inhibited by palmitoyl, lauroyl, oleoyl, myristoyl and stearoyl-CoA esters, glutamate and glucose 6-phosphate but not by acetyl-CoA or shorter chain fatty acyl-CoA esters. The enzyme exhibited normal Michaelis-Menten kinetics for citrate; however there was a 3-fold increase in Km with a high concentration of Cl- ions (0.25 M). The possible regulatory roles of ATP:citrate lyase in R. gracilis are discussed in the light of these findings.
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PMID:ATP:citrate lyase of Rhodotorula gracilis: purification and properties. 230 11

Hexon capsomers of human adenovirus type 1 (h1) labeled by iodine 125 were digested in a native state (trimers) by trypsin, chymotrypsin or papain, and the resulting hydrolysates were analyzed by SDS-PAGE. In each case, a discrete and temporally stable pattern of relatively large fragments was revealed. The degree of hexon polypeptide hydrolysis was maximal for papain, intermediate for chymotrypsin and minimal for trypsin, the largest fragments in the digest being 32, 40 and 80 kD, respectively. At room temperature, all the electrophoretically discernible hexon proteolytical fragments were held together in structures resembling intact hexon trimers and could be regarded as "hexon cores", of which papain hexon cores were the most stable during SDS-PAGE. Radioimmunoprecipitation analysis revealed a complete absence of native hexon antigenicity in thermodenaturated fragments of hexon protease digests, while native trypsin, chymotrypsin and papain hexon cores could be precipitated by hexon-specific antibodies. The immunoprecipitated material contained all of the hexon fragments found in appropriate hexon cores and retained the structure of the original cores. Trypsin, chymotrypsin and papain hexon cores were shown to possess at least part of native Ad h1 hexon antigenic determinants of each of the following specificities: species-specific (epsilon), cross-reactive with hexon of human adenoviruses (h3 and h6), simian adenovirus (sim 16), bovine adenoviruses (bos 3 and bos 7) and avian adenovirus (Aviadenovirus gal 1 or CELO). Thus, the full spectrum of known hexon antigenic determinants (species-specific to intergenus-crossreactive) is at least portly stable against protease attack of native hexon capsomers.
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PMID:[Stability of the structure and antigenic determinants of adenovirus type 1 native hexon to proteases]. 242 9

Trypsin treatment of recombinant PDGF-BB from Escherichia coli leads to the liberation of a small carboxy-terminal fragment and two internal segments without dissociating the molecule. The remaining core of 21 kDa retained a considerable binding affinity of 8.4 nM. By use of various peptide fragments obtained from monomeric recombinant PDGF-B, a receptor binding domain was assigned to one of these internal trypsin-sensitive segments. This segment is enriched in charged residues, suggesting mainly hydrophilic interactions with the receptor. Circular dichroism measurements of recombinant PDGF-BB showed a high content of random structure and only a small percentage (less than 10%) of alpha-helical structures. This structure was very rigid since the addition of 70% trifluoroethanol or 1% SDS did not change the circular dichroism spectrum. On the basis of these results, a tentative structure was generated by computer modeling.
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PMID:Binding domains and epitopes in platelet-derived growth factor. 247 33

The organisation of extracellular matrix beneath the human amniotic epithelium was investigated in order that the co-ordinate synthesis of basal lamina and stroma by these cells could be better understood. Transmission electron microscopy of intact tissue confirmed that stromal matrix fibrils are located between the cell surface and the basal lamina, and also penetrate the lamina. The distribution of the supralaminal fibrils and their association with the lamina was further investigated by scanning electron microscopy (SEM) after removal of the overlying epithelium. Five complementary procedures were used to remove the cells from the underlying lamina. Trypsin-EDTA treatment caused the epithelial cells to retract or detach from the lamina. SDS or ammonium hydroxide was used to extract the epithelium, which was then removed by physical shearing. Transmission electron microscopy (TEM) confirmed that the lamina densa and supralaminal fibres were present after extraction by these agents. Incubation in CHAPS, a zwiterionic detergent, did not remove the epithelium but permitted exposure of the basal lamina by mechanical scoring. Extraction with boric acid followed by osmium tetroxide produced epithelial disruption and revealed the lamina and stroma in different areas. Although the extraction pattern was different in each case, all of the five methods confirmed that individual fibrils and fibril bundles are present on the apical surface of, and enter, the lamina densa. Examination of the stromal surface of the basal lamina after fracture revealed fibrils passing from the stroma into the lamina densa. We therefore suggest that, in this tissue, newly synthesised stromal matrix components appear in an assembled fibrillar form between the basal cell surface and the basal lamina before becoming associated with the sublaminal stroma.
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PMID:The translaminal fibrils of the human amnion basement membrane. 262 Dec 27

Trypsin from pyloric caeca of Pacific salmon was purified by affinity chromatography of the water extract on hexamethylenediamine-glycidylmethacrylate-cellulose. A protein band with a molecular weight of 22.5 kDa was found on SDS-electrophoresis in PAG. The protein band was homogeneous according to isoelectrofocusing in PAG (pI 4.0). The amino acid composition of the enzyme is typical of trypsin anionic forms; the major difference from the cationic forms is the lower content of lysine. The differences in properties caused by change of the enzyme molecule charge are similar to those observed in cationic trypsin when the lysine epsilon-amino groups of the latter are modified (change of pI, shift of the pH-optimum towards basic values, increase of stability to autolysis). Some natural trypsin inhibitors of the different origin suppressed the enzyme activity of trypsin from Pacific salmon in typical stoichiometric ratios. An unusual interaction of the enzyme with the specific inhibitor N-L-tosyl-L-lysine chloromethyl ketone was observed.
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PMID:[Preparation and properties of trypsin from the pyloric caeca of Pacific Ocean salmon]. 268 96

The polypeptide composition of unfertilized, fertilized, and protease-treated zona-free mouse eggs was evaluated in this study. Zona-free eggs were radioiodinated by an Iodogen-catalyzed reaction. Light microscopic autoradiography of egg sections revealed that labeling was restricted to the cell surface. Labeled eggs were solubilized, and cell surface polypeptides were identified by one-dimensional SDS polyacrylamide gel electrophoresis and autoradiography. The unfertilized egg demonstrated 8-10 peptides that incorporated 125I, with major bands observed at approximately 145-150, 94, and 23 kilodaltons (kD). Zona-free eggs fertilized in vitro and then radiolabeled demonstrated several new bands in comparison to unfertilized eggs, with a major band appearing at approximately 36 kD. Treatment of radiolabeled unfertilized eggs with either trypsin or chymotrypsin (1 mg/ml for 5-20 min) caused enzyme-specific modifications in labeled polypeptides. Trypsin (T) treatment resulted in time-dependant modification of the three major peptides at 145-150, 94, and 23 kD. Chymotrypsin (CT) treatment, in contrast, was associated with loss or modification of the 94 kD band, with no apparent effect on either the 145-150 or 23 kD band. Taken together with previous data indicating that T or CT egg treatment interferes with sperm-egg attachment and fusion (Boldt et al.: Biol Reprod 39:19-27, 1988), these results suggest a possible role for the 94 kD protein in sperm-egg interaction.
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PMID:Characterization of cell surface polypeptides of unfertilized, fertilized, and protease-treated zona-free mouse eggs. 274 6

The topography of chloroplast cytochromes f and b6 was probed with proteases carboxypeptidase A (CpA), trypsin, and Staph, aureus V8. The cytochrome and its proteolytic products were detected by heme stain and, in most experiments, by immunoreaction. In thylakoids, the only protease that significantly affected the intactness of cytochrome f was CpA that caused a small (delta Mr = -1-2000) decrease in the apparent molecular weight. In SDS-treated thylakoids, both trypsin and V8 degraded cytochrome f. The inferred topography of cytochrome f., with the COOH-terminus on the stromal (n) side, one membrane-spanning alpha-elix near the COOH-terminus, and most of the Cyt f mass on the lumen (p) side, is consistent with that previously inferred by others. Cytochrome b6 was not sensitive to CpA, but was more sensitive to trypsin and V8 protease than cytochrome f, cytochrome b-559, or the 17 kDa OEC extrinsic protein. Trypsin caused a small decrease in size of cytochrome b6, which was observed using whole protein antibody as a single smaller band (delta Mr approximately 2000) or two smaller discrete bands (delta Mr = -1000 and 2500, respectively) which, unlike the untreated protein, did not react with antibody generated to a peptide mimicking Asp-5-Gln-14 near the NH2-terminus. These shortened tryptic fragments were attributed to cleavage after R-10 and K-23 near the NH2-terminus, implying an orientation with the NH2-terminus on the stromal side of the membrane. The sensitivity of cytochrome b6 toward this trypsin cleavage was increased if the membranes were first incubated with CpA, showing that the NH2-terminal region of cytochrome b6 is masked by the COOH-terminal domain of one or more thylakoid proteins.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Topography of the chloroplast cytochrome b6: orientation of the cytochrome and accessibility of the lumen-side interhelix loops. 276 55

The coat protein of particles of sweet potato feathery mottle potyvirus (SPFMV) extracted from Ipomoea spp. migrated in SDS-PAGE mainly as bands of M(r) 38,000 (38K), 36K, 32K, 30K. Trypsin treatment of the particles resulted in the appearance of only one 30K polypeptide. The inclusion of protease inhibitors in the extraction procedure did not alter the heterogeneity of SPFMV coat protein. A partially purified fraction of extracts from recovering, symptomless, but not from healthy leaves of I. nil had a proteolytic activity similar to that of trypsin. Amino acid sequencing showed that the trypsin-cleaved 30K polypeptide had some sequence homology with other potyvirus coat proteins. The site at which the Ipomea extract cleaved the protein was five amino acids nearer the N terminus than trypsin cleavage site.
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PMID:Partial cleavage of sweet potato feathery mottle virus coat protein subunit by an enzyme in extracts of infected symptomless leaves. 276 26


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