We perform rigorous in-house testing on each batch of phosphocellulose paper to ensure you are provided with a high quality product. Our testing involves a standard kinase assay, in which AMP-activated protein kinase (AMPK) transfers radiolabeled gamma-phosphate from 32P-ATP to a purified peptide substrate (SAMS). We reject batches with high background, low binding capacity or signs of deterioration, relative to the previous Whatman P81 paper provided by GE Healthcare.
Results typically obtained from our in-house testing. Note low background binding.
Enzyme blank: SAMS peptide (100 µM) + 5 mM MgCl2 + 200 mM [γ-32P] ATP + 50% HOAc.
Basal: AMPK, SAMS peptide (100 µM) + 5 mM MgCl2 + 200 mM [γ-32P] ATP was incubated for 10 min at 30 ˚C, and the reaction quenched with 50% HOAc.
For each, 25 µL reaction volume was spotted onto a 2x2cm square of phosphocellulose paper, dried and washed 3x with 1% H3PO4. 32P transfer to the SAMS peptide was quantified by liquid scintillation counting (Perkin Elmer).
References: Ngoei KRW et al (2018) Cell Chemical Biology, 25:728-737; Glass DB et al (1978) Analytical Biochemistry 87:566-75
Of course, we understand each application varies. For peace of mind before purchasing we can provide a free sample sheet to new customers to test in your own laboratory. All we ask is that you cover the cost of shipping.