The phosphoglucomutase (PGM) from @entity20196 , which had been cloned and expressed in @entity526 , has been studied. After expression, the enzyme was purified from the @entity526 in a three-step process consisting of @entity4859 precipitation, gel filtration and anion-exchange chromatography. The purified enzyme gave one band on gel electrophoresis and was judged essentially free of impurities, although it was unstable when diluted without the addition of 15 microM BSA. The isoelectric point for A. xylinum PGM was 4.8 and the molar absorbance was 3.9 x 10(4) M-1.cm-1. The enzyme was reasonably heat-stable below 50 degrees C and was stable throughout the pH 5.5-7.4 range, but was 70% inactivated at pH 10.0 and completely inactivated after standing for 10 min at pH 3.0 or at pH 12.4. When isolated, the recombinant enzyme was fully active without the addition of extra @entity1025 . The Km for @entity13993 was much higher than that of other PGM species reported, which accords with the production of extracellular cellulose in A. xylinum. @entity27435 is not considered to be a substrate or coenzyme but an activating cofactor like Mg2+. The following kinetic constants were determined: Vmax 81.1 units/mg; kcat and the turnover rate 135 s-1; Km ( @entity27435 ) 0.2 microM; Km ( @entity13993 ) 2.6 mM; kcat/Km ( @entity13993 ) 5.2 x 10(4) M-1.s-1. The recombinant enzyme is considered to follow a characteristic substituted enzyme or Ping Pong reaction mechanism.

Studies on recombinant XXXX alpha-phosphoglucomutase.

@entity27435 :: ('MESH:C016473', 'Chemical') :: ['glucose 1,6-diphosphate', 'Glucose 1,6-diphosphate'] @entity1025 :: ('CHEBI:18420', 'Chemical') :: ['Mg2+'] @entity4859 :: ('CHEBI:62946', 'Chemical') :: ['(NH4)2SO4'] @entity20196 :: ('28448', 'Species') :: ['Acetobacter xylinum'] @entity13993 :: ('MESH:C031590', 'Chemical') :: ['glucose 1-phosphate'] @entity526 :: ('562', 'Species') :: ['Escherichia coli', 'E. coli']
@entity20196 :: (28448,Species) :: ['Acetobacter xylinum']
