| Summary: | 碩士 === 東海大學 === 食品科學系 === 82 === UDP-galactose 4-epimerase isolated from E.coli ATCC 27797 by
using preparative electrophoresis instead of the last three
steps of purification showed specific activity of 500 units per
milli- gram,two hundred and ninety folds,and overall avarage
activity recovery of 7 %.Synthetic diastereoisomers Rp-and Sp-
UDPα S- glucose have been seperated by using semipreparative
uBondpak C18 column and 50 mM phosphate buffer,pH 6.0 with high
performance liquid chromatography.The diastereospecificity of
UDP-galactosepimerase.The results showed that the epimerase
showed a rigid conformation of binding site around the Pα of
the substrate that .Rp-UDPαS-glucose (Km 2.7) seemed to be a
much better substrate than Sp-UDPα S-glucose (Km 25).The
location of Cysteine around the active site have been tested by
reacting with thiol reagentB and diamide.Base on the change in
activity and,fluoresence and electrophoresis result,if was
tentatively concluded that there are two thiols around the
active site and it is far fromother for making a disulfide bond
by oxidation.
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