Problems with beta-Galactosidase and X-Gal

Wolfgang Resch wresch at
Mon Mar 9 11:21:31 EST 1998

hi there !

try CPRG (don't ask me for the chemical name). it's a bata-Gal substrate
that produces soluble products that can be measured in spec. It's used to
determine beta-Gal activity in cell extracts/sups.
supplied by boehringer mannheim.


> I am searching for a method to examine funghi for
> extracellular beta-galactosidase activity.
> Right now I am using X-Gal
> (5-bromo-4-chloro-3-indonyl-beta-D-galactopyanoside) as
> substrate for this enzyme. I add a (low concentrated) X-Gal
> solution to the medium of the funghi. 24 hours later I check
> the medium for  blue coloring. I think that I see blue
> enzyme-pigment complexes in the medium, because of the
> unsolubility of the blue complex.
> Well, at least it DOES work, but the results are
> unsufficient reproducible, quantitative and reliable. I know
> that the use of X-Gal in this case is rather unusual, but I
> saw no other way to carry out this task ia a easy and simple
> way.
> - I know that X-Gal is actual unsoluble in water. But what
> about the blue complex after X-Gal has been spit by the
> enzyme?
> - Does anybody know a "smart" method to do this thing
> another way or improve the reliability of this test?
> - Does anybody know something about the stability of aquatic
> X-Gal-solutions? (In my opinion they degrade quite rapidly
> even at storage temperatures of 2-8 degrees celsius)
> I would be very happy for any tips and hints that could help
> me to solve this problems!
> thank you very much!
> Jochen, Germany
> (please forgive me my very awkward English!)   <- is this
> correct, after all?   :-)

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