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Figure 3.
Figure 3. Characteristics of coexpressed WT+F12L. (a)
Separation of two peaks of PBGS protein on Q-Sepharose; KCl
gradient (red line), A (black
line). Both pools showed PBGS activity at pH 7 (  )
and at pH 9 (  ).
(b) The mobility of the two pools of WT+F12L relative to
wild-type (WT) human PBGS and the F12L variant on native gel
electrophoresis. (c) The pH-rate profiles for pool I ( )
and pool II ( )
after further purification on Sephacryl S300. (d) Determination
of K[m] and V[max] values for the S300 purified pool I ( )
and pool II ( [280][glyph.gif] ) at pH 7 (black) and pH 9 (red).
Dashed lines indicate the poor fits to standard hyperbolic
saturation kinetics. Solid lines indicate the superior fit to a
double hyperbola model where two forms of the enzyme are
catalyzing the same reaction (see text and Table 1).
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