Stability of ATP (to hydrolysis) is pH dependent, and even the disodium ATP is strongly acidic in distilled water. I used to make 100 mM ATP by dissolving disodium or Na,K-ATP in ~100 mM NaOH, getting pH ~6-7.
This suggests 8.3 would be better: http://www.patentstorm.us/patents/6916616/description.html Also, the standard phosphate assay hydrolyzes ATP pretty rapidly, so people measuring ATPase use a special assay with milder conditions- names like Fiske-Subbarow and Lohman-Jendrassick come to mind, but not sure if either is the one suitable for ATP. No I think it was the Lowry-Lopez method which uses ascorbic acid at pH 4 instead of ANS as the reducing reagent. dengzq1987 wrote:
Dear all, recently, i prepared the ATP solution used to assay ATPase activity. when the Control Well just containing assay buffer and ATP mixed with molybdate ,the colour changed to green, this mean that there is free pi in the solution.the assay buffer and water is free from pi.and the ATP stock solution has free pi ,maybe the ATP hydrolysis when prepared .any suggestion about preparing ATP stock solution is appreciative. Best regards! 2010-08-29 ------------------------------------------------------------------------ dengzq1987
