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Problems with beta-Galactosidase and X-Gal

J. Jockers jjockers at metronet.de
Sun Mar 8 19:27:25 EST 1998


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

- I know that X-Gal is actual unsoluble in water. But what
about the blue complex after X-Gal has been spit by the
- 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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