Re: alkaline phosphatase

From:Ronnie Houston

Dear Adrian,

Sorry don't totally agree.

L-phenylalanine inhibits intestinal alkaline phosphatase; however I'm sure that if the concentration of any of the uncompetitive alkaline phosphatase inhibitors is used at a high enough concentration, it will inhibit most types. 

Remember the term alkaline phosphatase covers a large number of  phosphatases that will react on a wide range of substrates at alkaline pH.


Ronnie Houston
Cytochemistry & Molecular Pathology
Texas Scottish Rite Hospital for Children
2222 Welborn Street
Dallas, TX 75219
(214) 559 7744
(214) 559 7768 - fax

>>> nina leek  11/07/01 01:41PM >>>
Dear Ronnie and Carol:
Sorry guys,but, levamisole inhibits (or not) ALL alkaline phosphatases,
depending on its concentration.  The intestinal variety is the most
resistant, followed by the placental, with bone/liver/kidney-type being
inhibited by the lowest concentration.
Depending on what you are looking for, you could well get away with
putting 10mM levamisole in your substrate to reveal the (intestinal)
AlPase label and suppress (nearly) all the endogenous activity in the
kidney.  This concentration in the substrate may reduce the activity of
your label by 50-90%, but will reduce that of the kidney by 99% or
more.  If you expect only a faint label signal, and have a lot of
endogenous activity, this may not be enough of a difference, and an
inactivating pretreatment will be your best bet.  Conversely, a lot of
signal and only a little endogenous activity would let you use less
(very expensive) levamisole.  Always run the negative control.
Try it and see.
Good luck,
Adrian Leek.

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