Zhou J, Xu X, Liu W, Liu X, Nie Z, Qing M, Nie L, Yao S. Graphene oxide-peptide nanocomplex as a versatile fluorescence probe of protein kinase activity based on phosphorylation protection against carboxypeptidase digestion.
Anal Chem 2013;
85:5746-54. [PMID:
23734972 DOI:
10.1021/ac400336u]
[Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The research on complicated kinomics and kinase-target drug discovery requires the development of simple, cost-effective, and multiplex kinase assays. Herein, we propose a novel and versatile biosensing platform for the detection of protein kinase activity based on graphene oxide (GO)-peptide nanocomplex and phosphorylation-induced suppression of carboxypeptidase Y (CPY) cleavage. Kinase-catalyzed phosphorylation protects the fluorophore-labeled peptide probe against CPY digestion and induces the formation of a GO/peptide nanocomplex resulting in fluorescence quenching, while the nonphosphopeptide is degraded by CPY to release free fluorophore as well as restore fluorescence. This GO-based nanosensor has been successfully applied to sensitively detect two model kinases, casein kinase (CKII) and cAMP-dependent protein kinase (PKA) with low detection limits of 0.0833 mU/μL and 0.134 mU/μL, respectively. The feasibility of this GO-based sensor was further demonstrated by the assessment of kinase inhibition by staurosporine and H-89, in vitro kinase assay in cell lysates, and simultaneous detection of CKII and PKA activity. Moreover, the GO-based fluorescence anisotropy (FA) kinase assay has been also developed using GO as a FA signal amplifier. The proposed sensor is homogeneous, facile, universal, label-free, and applicable for multiplexed kinase assay, presenting a promising method for kinase-related biochemical fundamental research and inhibitor screening.
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