Enzymatic Assay of D-Xylose Isomerase Activity
نویسندگان
چکیده
منابع مشابه
Crystallographic studies of D-xylose isomerase.
* This work was supported by National Institutes of Health Grants CA-10925, CA-OG927, and RR-05539 from the United States Public Health Service and by an appropriation from the Commonwealth of Pennsylvania. (I), was crystallized from acetone. The enzyme from Bacillus coagulans has also been crystallized from ammonium sulfate solution and from aqueous acetone (3). We describe here preliminary x-...
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The mechanism of D-fructose isomerization by Arthrobacter D-xylose isomerase suggested from X-ray-crystallographic studies was tested by detailed kinetic analysis of the enzyme with various metal ions at different pH values and temperatures. At D-fructose concentrations used in commercial processes Mg2+ is the best activator with an apparent dissociation constant of 63 microM; Co2+ and Mn2+ bin...
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A partially purified D-xylose isomerase has been isolated from cells of Streptomyces albus NRRL 5778 and some of its properties have been determined. D-Glucose, D-xylose, D-ribose, L-arabinose, and L-rhamnose served as substrates for the enzyme with respective Km values of 86, 93, 350, 153, and 312 mM and Vmax values measuring 1.23, 2.9, 2.63, 0.153, and 0.048 mumol min per mg of protein. The h...
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Mutants of Arthrobacter D-xylose isomerase were constructed in which one or two disulphide bridges or additional salt bridges were introduced at the A-A* subunit interfaces. These showed no change in enzyme activity or stability compared with the wild-type enzyme. However, a Tyr253 mutant in which a disulphide bridge was introduced at the A-B* subunit interface showed reduced thermostability th...
متن کاملMetal ion binding to D-xylose isomerase from Streptomyces violaceoruber.
The binding of two activating cations, Co2+ and Mg2+, and of one inhibitory cation, Ca2+, to D-xylose isomerase from Streptomyces violaceoruber was investigated. Equilibrium-dialysis and spectrometric studies revealed that the enzyme binds 2 mol of Co2+/mol of monomer. Difference absorption spectrometry in the u.v. and visible regions indicated that the environment of the first Co2+ ion is mark...
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ژورنال
عنوان ژورنال: Agricultural and Biological Chemistry
سال: 1969
ISSN: 0002-1369,1881-1280
DOI: 10.1271/bbb1961.33.834