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  • 1
    Electronic Resource
    Electronic Resource
    Purification and immobilization of Aspergillus niger β-xylosidase (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 1127-1142 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: β-Xylosidase from a commercial Aspergillus niger preparation was purified by differential ammonium sulfate precipitation and either gel permeation or cation exchange chromatography, giving 16-fold purification in 32% yield for the first technique or 27-fold purification in 19% yield for the second. The second method in addition almost completely removed interfering β-glucosidase activity. Enzymes prepared by this method was immobilized to 10 different carriers, but only when it was bound to alumina with TiCl4 and to alkylamine porous silica with glutaraldehyde were substantial efficiencies and stabilities achieved. With alumina, the variation of activation procedure, amount of β-xylosidase offered, and activation solution composition yielded maximum activities of over 40 U/g with approximately 70% immobilization efficiency. Variation of binding pH and incubation time led to a maximum immobilized activity of 1.3 U/g with 78% immobilization efficiency on silica.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260220603
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  • 2
    Electronic Resource
    Electronic Resource
    Estimation of intrinsic kinetic constants for pore diffusion-limited immobilized enzyme reactions (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 23 (1981), S. 487-497 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A simple method is presented that establishes intrinsic rate parameters when slow pore diffusion of substrate limits immobilized enzyme reactions that obey Michaelis-Menten kinetics. The Aris-Bischoff modulus is employed. Data at high substrate concentrations, where the enzyme would be saturated in the absence of diffusion limitation, and at low substrate concentrations, where effectiveness factors are inversely proportional to reaction modulus, are used to determine maximum rate and Michaelis constant, respectively. Because Michaelis-Menten and Langmuir-Hinshelwood kinetics are formally identical, this method may be used to estimate intrinsic rate parameters of many heterogeneous catalysts. The technique is demonstrated using experimental data from the hydrolysis of maize dextrin with diffusion-limited immobilized glucoamylase. This system yields a Michaelis constant of 0.14%, compared to 0.11% for soluble glucoamylase and 0.24% for immobilized glucoamylase free of diffusional effects.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260230303
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Immobilization and properties of Leuconostoc mesenteroids dextransucrase (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 1055-1069 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Dextransucrase from Leuconostoc mesenteroides (NRRL B-512F) was purified by ultrafiltration and gel filtration chromatography in 54% yield. The specific activity of a heart cut was 58.6 U/mg; cumulative purification of that preparation was 247-fold. Of 13 carriers surveyed, only alkylamine porous silica gave immobilization efficiencies consistently above 15 %. Immobilization to silica changed the properties of dextransucrase relatively little, the optimum pH for activity remaining at 5.2, while that for stability decreased from pH 5.5-6 to pH 5.2. In short assays, highest activities of both soluble and immobilized dextransucrase occurred at 30°C. Activation energies below that temperature were 8.6 kcal/mol for the former form and 1.7 kcal/mol for the latter. Maximum stabilization of soluble dextransucrase was attained by 5mM Ca2+.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260220513
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of pore diffusion limitation on dextrin hydrolysis by immobilized glucoamylase (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 1-17 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Data reported here and previously indicate that when dextrin is hydrolyzed in the presence of immobilized glucoamylase, use of a larger average molecular weight substrate leads to lower overall rates of hydrolysis, while the maltose concentration during the bulk of the reaction and the maximum glucose concentration are lower than when the soluble form of the enzyme is employed under the same conditions. Computer simulation of the system demonstrated that all three observations were caused by pore diffusion limitation: the first by slow diffusion of substrate, the second by slow diffusion of intermediates, and the third by slow diffusion of glucose. Follow-up experiments with glucoamylase immobilized to particles of different sizes confirmed this finding, as results with the smallest beads were identical to those with soluble glucoamylase.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260220102
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  • 5
    Electronic Resource
    Electronic Resource
    Properties of soluble and immobilized Aspergillus niger β-xylosidase (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 1143-1154 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Aspergillus niger β-xylosidase was characterized when in soluble form and when immobilized to alkylamine porous silica with glutaraldehyde and to alumina with titanium tetrachloride. Energies of activation averaged 13.4 KcaL/mol for the soluble enzyme, 9.0 Kcal/mol when immobilized to alumina, and 8.0 Kcal/mol when bound to silica. The highest activity of all forms of β-xylosidase was found near pH 3. The soluble enzyme was highly stable at pH 4, where lowest rates of decay occurred, and temperature of 65°C and below. The decay rates of alumina-bound β-xylosidase and pH 4 and equivalent temperatures were approximately 10 times as high. Michaells constants were 0.200 and 0.262mM for o-nitrophenyl-β-D-xylopyranoside with soluble and alumina-bound β-xylosidase, respectively.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260220604
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Use of immobilized glucoamylase-β-amylase and glucoamylase-fungal amylase mixtures to produce high-maltose syrups (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 1753-1758 
    Details
    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
    URL: http://dx.doi.org/10.1002/bit.260220816
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  • 7
    Electronic Resource
    Electronic Resource
    Author index entries for “Immobilization of leuconostoc mesenteroides dextransucrase to porous phenoxyacetyl cellulose Beads” (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 24 (1982), S. 1928-1928 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: No. Abstract.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260240824
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  • 8
    Electronic Resource
    Electronic Resource
    Immobilization of leuconostoe mesenteroides dextransucrase to porous phenoxyacetyl cellulose beads (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 23 (1981), S. 2647-2653 
    Details
    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
    URL: http://dx.doi.org/10.1002/bit.260231120
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  • 9
    Electronic Resource
    Electronic Resource
    Two-dimensional immunoelectrophoresis of rat serum apolipoproteins (1981)
    Weinheim : Wiley-Blackwell
    Electrophoresis 2 (1981), S. 113-116 
    Details
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A two-dimensional crossed immunoelectrophoretic method for the determination of the specificity of antibodies raised against rat serum lipoproteins and apolipoproteins (Apo) is described. The method may also be used for the detection of as yet undesignated apoproteins, associated with the serum lipoprotein fractions, and exploits the superior resolving capacity of 7m urea 10% polyacrylamide gel electrophoresis for the first dimension separation and minimizes physical separation of polyacrylamide and agarose in the second dimension electrophoresis by use of low electroendosmotic flow agarose. The use of polyacrylamide instead of cellulose acetate in the first dimension permits the analysis of larger amounts of antigen protein, crossed imunoelectrophoresis of Apo E which binds to cellulose acetate, and the crossed immunoelectrophoresis of antigens previously focused to their isoelectric points in polyacrylamide gels containing ampholytes.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150020208
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