title: Carbon nanotube-enhanced polarization of fluorescent peptides: a novel amplification strategy for homogeneous detection of proteases.
abstract: A new fluorescence polarization (FP) amplification strategy based on the use of multiwalled carbon nanotubes (MWCNTs) as the FP enhancer was developed for the simple, sensitive, and universal monitoring of protease activity in homogeneous solution. A fluorophore-labeled peptide that includes a protease-cleavable element and ten histidine residues for binding MWCNTs is adsorbed on MWCNTs through strong π-π stacking and electrostatic interactions. When the fluorophore-labeled peptide/MWCNT complexes are exposed to a protease target, specific peptide cleavage by the protease target occurs, thus releasing fragments carrying the fluorophore from the surface of MWCNTs, which in turn results in a significant decrease in the FP value. The detection limits of this assay for two proteases, thrombin and chymotrypsin (CTP), were estimated to be 0.5 pM and 0.3 pM, respectively. In addition, it is also demonstrated that this MWCNT-enhanced FP assay is suitable for protease inhibitor screening.
authors.affiliation: Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), College of Chemistry and Pharmacy, Guangxi Normal University, Guilin 541004 (China), Fax: (+86) 773-583-2294.
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
authors.forename: Kun
authors.initials: K
authors.lastname: Hu
authors.forename: Shulin
authors.initials: S
authors.lastname: Zhao
authors.forename: Mei
authors.initials: M
authors.lastname: Li
authors.forename: Zhen-Feng
authors.initials: ZF
authors.lastname: Chen
authors.forename: Qiuju
authors.initials: Q
authors.lastname: Lv
authors.forename: Hong
authors.initials: H
authors.lastname: Liang
mesh_terms: D002918:Chymotrypsin / Q000032:analysis* / Q000378:metabolism; D005454:Fluorescence Polarization; D005456:Fluorescent Dyes / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D013917:Thrombin / Q000032:analysis* / Q000378:metabolism
chemical_list: D005456:Fluorescent Dyes; D037742:Nanotubes, Carbon; D010455:Peptides; D002918:Chymotrypsin; D013917:Thrombin
keywords: biosensors; fluorescence polarization; inhibitors; nanotubes; protease