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  • 1985-1989  (2)
  • 1975-1979  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Active site studies on Bacillus amyloliquefaciens α-amylase (I) (1985)
    Springer
    Molecular and cellular biochemistry 66 (1985), S. 13-20 
    Details
    ISSN: 1573-4919
    Keywords: active site ; α-amylase ; Bacillus amyloliquefaciens ; chemical modification ; diethylpyrocarbonate ; histidine ; rose bengal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary Modification of liquefying α-amylase by diethylpyrocarbonate or its photo-oxidation in the presence of rose bengal caused rapid loss of enzyme activity. The photo-oxidation followed pseudo-first-order kinetics giving maximal value at pH 8.0. The photo-oxidized enzyme showed a characteristic increase in absorbance at 250 nm which was directly proportional to the extent of inactivation. Diethylpyrocarbonate at low concentration at pH 6.0 and 30 ° C completely inactivated a-amylase. Inactivation followed pseudo-first-order kinetics. The reaction order with respect to inactivation by diethylpyrocarbonate was one, thus indicating modification of a single histidine per mole of the enzyme. Diethylpyrocarbonate-modified enzyme showed increased absorbance at 240 nm which was reversed completely upon treatment with NH2OH at 30 °C for 16 hr. Calculating the histidine residues being modified from the increase in absorbance at 240 nm showed that three residues were ethoxyformylated on treatment with diethylpyrocarbonate, of which only one was found at the active site. Substrate and competitive inhibitor protects the enzyme against both, photo-oxidation, and modification by diethylpyrocarbonate, confirming that histidine plays an essential role at the α-amylase active site.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231818
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    A rapid and powerful method for the direct gas chromatographic analysis of alkanolamines; Application to ethanolamines (1977)
    Springer
    Chromatographia 10 (1977), S. 368-371 
    Details
    ISSN: 1612-1112
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The problems of derivative gas chromatography of the alkanolamines have been discussed. It has been demonstrated that the difficulties of direct GC, inherent in the high adsorption affinity and strong retentive interaction of this class of compounds with silaceous supports and stationary liquids, can be overcome by using organic polymer beads, having weakly interacting surface. From a short column containing Tenax-GC under programmed temperature conditions, better than base line resolution of the three ethanolamines can be achieved in less than 8 minutes, as against about an hour by derivative GC and several hours by chemical methods, based on amine functionality. Elution properties, such as retention index and its temperature coefficient, have been determined on Tenax-GC for the ethanolamines. A boric acid precolumn is reported for the first time to completely subtract the alkanolamines. The relative response factors, which are required for precision analysis, have been found to make an interesting comparison for the ethanolamines and their derivatives. Under optimised PTGC conditions, a 4 ft Tenax-GC column has revealed the presence of six impurity peaks with fairly good resolution in a commercial sample of triethanolamine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02274486
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Carboxypeptidase a immobilization on activated styrene-maleic anhydride systems (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 675-680 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The copolymer styrene-maleic anhydride (SMA) was activated to various forms to create enzyme coupling groups. Carboxypeptidase A (CPA) was Immobilized on these supports to enhance their thermal and chemical stability. Immobilized enzyme retained 60-70% of the original activity. When kept at 60°C, while free enzyme was deactivated within 30 min, the immobilized enzyme retained 40% of initial activity at the end of 3 h. The half-life of free enzyme was only 21 min, while for immobilized enzyme it was enhanced up to 3 h. Also, the immobilized enzyme could be repeatedly used over 50 times retaining almost 50% of original activity.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270517
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  • 4
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    A rapid and powerful method for the direct gas chromatographic analysis of alkanolamines; Application to ethanolamines (1977)
    Springer
    Details
    Publication Date: 1977-07-01
    Print ISSN: 0009-5893
    Electronic ISSN: 1612-1112
    Topics: Chemistry and Pharmacology
    Published by Springer
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  • 5
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    Studies on characterization and variation in triglyceride fatty acids from punt/us sarana body lipids (1978)
    Wiley
    Details
    Publication Date: 1978-12-01
    Print ISSN: 0003-021X
    Electronic ISSN: 1558-9331
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Published by Wiley
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