bGal reporter Q

Mark Bowen mb at
Tue Jun 29 09:21:44 EST 1999

I am trying to develop a quantitative transcription assay (in E. Coli)
using bGalactosidase.  My feeling is that my results will be more
reliable/quantitative if the entire bGal is under the control of my
promoter rather than just the alpha-peptide.  Has anyone looked at this
or is anyone aware of references dealing with this?   

	The logic being that if I'm only driving alpha-peptide expression I
don't fully control the enzymatic activity I'm measuring because
variability in the level of the other subunit would affect the amount of
active enzyme and would not be regulated.  Even in conditions where the
non-regulated subunit is in excess, the concentration could affect the
steady-state level of active enzyme depending on the magnitude of their
binding constants. The down side of including all of bGal is that it is
huge and my plasmid is already big.

Mark Bowen

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