A mix-and-read fluorescence strategy for the switch-on probing of kinase activity based on an aptameric-peptide/graphene-oxide platform.

Abstract

Protein kinase plays a vital role in regulating signal-transduction pathways and its simple and quick detection is highly desirable because traditional kinase assays typically rely on a time-consuming kinase-phosphorylation process (ca. 1 h). Herein, we report a new and rapid fluorescence-based sensing platform for probing the activity of protein kinase that is based on the super-quenching capacity of graphene oxide (GO) nanosheets and specific recognition of the aptameric peptide (FITC-IP20). On the GO/peptide platform, the fluorescence quenching of FITC-IP20 that is adsorbed onto GO can be restored by selective binding of active protein kinase to the aptameric peptide, thereby resulting in the fast switch-on detection of kinase activity (ca. 15 min). The feasibility of this method has been demonstrated by the sensitive measurement of the activity of cAMP-dependent protein kinase (PKA), with a detection limit of 0.053 mU μL(-1). This assay technique was also successfully applied to the detection of kinase activation in cell lysate.