Alkaline Phosphatase assays, p-nitrophenyl phosphate stock soln.
Altaf A. Wani
wani.2 at osu.edu
Thu Feb 4 09:39:18 EST 1999
For our Ap assay (mainly ELISA related) we dissolve PNPP at 1 mg/ml in 1 M
diethanolamine buffer, pH 9.5; 5 mM MgCl2. You could prepare a stock
substrate solution and store it in cold as long as it does not turn yellow
over time due to hydrolysis. Best way is to prepare fresh before use. We use
prepacked 5 mg tablets from sigma and just add them to a 5 ml buffer
solution before assay. Good Luck.
The Ohio State University
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