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  • Analytical Chemistry and Spectroscopy  (32)
  • Biochemistry and Biotechnology  (16)
  • 1
    ISSN: 0887-3585
    Keywords: proteolytic cleavage ; immunological cross-reaction ; amber fragment ; temperature-sensitive mutant ; stationary growth-phase ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Immunological cross-reaction was employed for identification of proteolytic fragments of E. coli RNA polymerase genered both in vitro and in vivo. Several species of partially denatured but assembled RNA polymerase were isolated, which were composed of fragments of the two large subunits, β and β′, and the two small and intact subunits, α and σ. Comparison of the rate and pathway of proteolytic cleavage in vitro of unassembled subunits, subassemblies, and intact enzymes indicated that the susceptibility of RNA polymerase subunits to proteolytic degradation was dependent on the assembly state.Using this method, degradation in vivo was found for some, but not all, of the amber fragments of β subunit in merodiploid cells carrying both wild-type and mutant rpoB genes. Although the RNA polymerase is a metabolically stable component in exponentially growing cells of E. coli, degradation of the full-sized subunits was found in two cases, i.e., several temperature-sensitive E. coli mutants with a defect in the assembly of RNA polymerase and the stationary-phase cells of a wild-type E. coli. The in vivo degradation of RNA polymerase was indicated to be initiated by alteration of the enzyme structure.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 7 (1990), S. 93-98 
    ISSN: 0887-3585
    Keywords: protein conformation ; CONGEN ; immunoglobulin ; hydrogen bond ; digoxin ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The mouse hybridoma cell line 40-150 scretes antibodies with high affinity towards the cardiac glycosides digoxin and digitoxin. A spontaneous mutant, 40-150 A2.4, produces and antibody which carries a single residue mutation, Ser → Arg, in its heavy chain (H94) and has an altered specificity. A second order mutant 40-150 A2.4 P.10, produces two antibody molecules, one the same as 40-150 A2.4, the other lacking two residues at the N-terminus of its H chain, and having a specificity profile approaching that of 40-150 antibody. 1 The N-terminus and the position H94 are distant from the antigen-binding site of the antibody; thus, the structural basic of the specificity changes was not immediately clear. Approximate structures of the 40-150 antibody and its mutants were constructed in the computer, based on atomic coordinates of the homologous mouse antibody McPC 603. Using the program OCNGEN, the torsional space of the polypeptide backbone and side chains around position H94 was uniformly sampled, and the lowest energy conformations were analyzed in detail. The results indicate that when Arg-H94 is substituted for Ser. Agr-H94 can hydrogen bond to side chains of Asp-H101, Arg-L46, and Asp-L55. The results in a change in the surface of the combining site which may account for the affinity changes. Deletion of the two N-terminal residues increases solvent accessibility of Arg-H94. The solvation may cause a hydrogen bond between Arg-H94 and Asp-H101 to be lost, restoring the structure to one similar to that of 40-150.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 14 (1992), S. 465-474 
    ISSN: 0887-3585
    Keywords: conformational search ; directed searches ; α-carbon coordinates ; modeling ; structure prediction ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A directed conformational search algorithm using the program CONGEN (ref. 3), which samples backbone conformers, is described. The search technique uses information from the partially built structures to direct the search process and is tested on the problem of generating a full set of backbone Cartesian coordinates given only α-carbon coordinates. The method has been tested on six proteins of known structure, varying in size and classification, and was able to generate the original backbone coordinates with RMSs ranging from 0.30-0.87Å for the α-carbons and 0.5-0.99Å RMSs for the backbone atoms. Cis peptide linkages were also correctly identified. The procedure was also applied to two proteins available with only α-carbon coordinates in the Brookhaven Protein Data Bank; thioredoxin (SRX) and triacyiglycerol acylhydrolase (TGL). All-atom models are proposed for the backbone of both these proteins. In addition, the technique was applied to randomized coordinates of flavodoxin to assess the effects of irregularities in the data on the final RMS. This study represents the first time a deterministic conformational search was used on such a large scale. © 1992 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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  • 4
    ISSN: 0887-3585
    Keywords: crystallization ; folate ; multifunctional ; twinning ; dehydrogenase ; cyclohydrolase ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Methylenetetrahydrofolate([H4] folate) dehydrogenase (D) and methenyl[H4] folate cyclohydrolase (C) coexist as a bifunctional enzyme (DC) or as the amino-terminal domain of a trifunctional enzyme (DCS) where the third activity is 10-formyl[H4]lfolate synthetase (S). Two crystal forms of the DC domain of the human cytosolic DCS enzyme have been grown from polyethyleneglycol solution. The monoclinic P21 crystals diffract to 2.8 Å with a = 72.5 Å, b = 68.5 Å, c = 125.2 Å, and β = 91.8° but were found to be twinned. The orthorhombic P212121 crystals diffract to 2.5 Å with a = 67.7 Å, b = 135.9 Å, c = 61.6 Å, and contain two molecules per asymmetric unit. Proteins 26:479-480 © 1996 Wiley-Liss, Inc.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1659-1673 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Immobilized beef liver catalase has been used in a flow reactor to decompose hydrogen peroxide; at the same time the catalase is inactivated by its substrate. A model has been developed which predicts this rate of decomposition of peroxide and inactivation of catalase. First order dependence on peroxide concentration is assumed. The model was verified by experiment for a range of operating conditions and then used to predict the effects of a change in operating variables.
    Additional Material: 7 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 10 (1968), S. 625-640 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Studies of the possible viral etiology of human leukemia have required large quantities of cultured cells derived from human hematopoietic tissues. Since cultures sufficiently large and free from contamination could not readily be produced according to existing methods, a pilot, cell culture plant has been constructed for the production of mammalian cells in mass quantity. 500-ml to 20-liter trophocell units have already proved to be scientifically and economically practical, as they provide good reliability, excellent growth rates, and sustained yield of human cells. 200-liter stainless steel culture units have now been added to the trophocell system. Five complete 200 liter units are now in operation. The design of the original stainless steel unit was based on that of a stainless steel, jacketed soup kettle. There are no openings in the vessel other than those in the lid, which provide convenient access points for sampling, sensor probes, etc. Environmental parameters, e.g., liquid level, temperature, and pH, are monitored and controlled with commercially available apparatus. Many initial problems connected with the new 200 liter units have been resolved, but operational and design problems remain in the areas of stable instrumentation, cell harvesting, salvaging and reuse of unspent media components, establishment of physiologic steady stale, recovery of virus-containing cells with reculture of the remaining unaffected cells, and the recovery and separation of cell components and special products such as immunoglobulins, interferons, and hormones. A definitive cell plant with culture units of 20, 50, 250, and 1250 liters is now being constructed.
    Additional Material: 7 Ill.
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  • 7
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This study reports some findings on the effects of centrifugation on the viability of mammalian cells. The authors used Burkitt lymphoma cells cultivated in a synthetic medium containing 10% fetal calf serum for all experiments. Batch centrifugations were conducted in a RC2-B centrifuge (Ivan Sorvall, Incorporated, Norwalk, Connecticut USA) operated at 0 and 25°C. During centrifugation we exposed the cells to gravitational fields ranging from 24,800 to 42.200g. The results showed that at, 0°C and 25,800 or 42,000g no loss in cell viability occurred for up to 90 min exposures in the centrifugal field. However, at 25°C and for gravitational fields of 24,800 and 42,000g, there were appreciable losses in cell viability. Continuous centrifugation studies in the Sharples supercentrifuge (Division of Penn Salt Corporation, Warminister, Pennsylvania USA) were also conducted with bowl speeds up to 28,000 rpm (19,000g) and flow rates ranging from 1.4 to 20 1, hr. Slight, losses in cell viability were noted and postulated as caused by the shear stresses encountered by the cells. Some pumping studies using the lymphoma cells substantiate this conclusion.
    Additional Material: 4 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 20 (1978), S. 589-599 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Combining acid cottage cheese whey and the lime-sulfide effluent from tannery unhairing processes spontaneously coprecipitates the whey proteins with the large peptides and proteins of the tannery waste. The floculation of the denatured protein material also carries down the hide pigments, excess lime, and the casein fines from the whey. The clear supernatant contains lactose, sulfur in various states of oxidation, free amino acids, peptides, and ammonium salts, but no detectable macromolecular proteins. The recovered solid products, which contain more than 20% of the original nitrogen, appear to have a good balance of essential amino acids although actual composition varies with the composition of the raw wastes. Feed supplements may possibly by obtained by this method from two presently wasted industrial effluents.
    Additional Material: 2 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1675-1680 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 20 (1997), S. 643-646 
    ISSN: 0935-6304
    Keywords: Capillary electrophoresis ; Electogenerated chemiluminescence ; Ru(bpy)32+ ; Tripropylamine ; Proline ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A post- column chemiluminescent technique for thedetection of compounds that are poor chromoshores using electorogenerated chemiluminescence following separation by capillartgy electrophoresis is described. The luminrescent signal is generated followintg the reaction of anlyres (e.g. amines) with Ru(bpy)33+, which isx electrochemically generated post-columan from Ru(bpy)32+. Tripropylamine and proline are used as two model compounds to demostrate the feasibility of the method. Detection limits for the prototype system were in the micromolar rage, suggesting that this technnique offers an alternative to indirect detection of compounds that are poor chromophores with an added selectivity advangage. The system includes the use of a conductive joint to isolate the separation field from the potential necessary to drive the elctrogenerated chemiluminescent reactiion. Addition of the chemiluminescent reagent Ru(bpy)32+ post-column did not decrease the efficiency of the separation. The design and favrication of the novel cell is discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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