LSA-50 paper: An alternative to P81 phosphocellulose paper for radiometric protein kinase assays

Radiometric assays have widely been used for measuring protein kinase activity for decades. In addition, several non-radiometric kinase assay formats have been developed over the years, including luciferase-based and fluorescence-based assays. However, radiometric assays are still considered as the “gold standard” for protein kinase assays, because of their direct readout, high sensitivity, reproducibility, reliability, and very low background signals. These radiometric assays rely on P81 phosphocellulose paper to capture the phosphorylated substrate and wash out unreacted [γ-32P] ATP. However, recently the production of P81 was discontinued by the manufacturer, causing major concern within the protein kinase research community. The advantages of radiometric assays over other kinase assay methods call for an urgent alternative to the discontinued P81 paper. In this report, we demonstrate that the LSA-50 paper is a worthy alternative for radiometric protein kinase assays originally using P81 phosphocellulose paper. [Display omitted] •P81 phosphocellulose paper, the gold standard for radiometric kinase assays, was discontinued.•Thus, an alternative paper for radiometric kinase assays is urgently needed.•Efficiency of P81 and LSA-50 paper in radiometric kinase assays was compared.•Kinase activities and inhibitor IC50's were very similar for P81 and LSA-50 paper.•LSA-50 paper is a high-quality alternative for P81 paper in radiometric kinase assays.