1.Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, The Institute for Advanced Studies, and Wuhan Institute of Biotechnology,Wuhan University,Wuhan,People’s Republic of China
Abstract:
Patients with prostate cancer and systemic lupus erythematosus exhibit reduced DNase I activity, and patients with myocardial infarction exhibit increased DNase I activity. So the assay of DNase I is of high importance. A colorimetric assay is described here for the determination of the activity of DNase. It is based on strand scission of dsDNA as catalyzed by DNase I. The products of digestion (nucleoside monophosphates) can better stabilize citrate capped AuNPs than dsDNA. In the absence of DNase I, the AuNPs aggregate in presence of NaCl and then display a blue color. In the presence of the analyte (DNase I), AuNPs do not aggregate but rather remain dispersed and display a red color. These findings were exploited to design a DNase I activity assay that is based on the measurement of ratio of absorbances at 520 nm (red) to 650 nm (blue). The detection limit for DNase I activity is found to be 7.1 U?L?1. In our perception, this assay has a large potential with respect to diagnoses of DNase I activity-related diseases and in drug screening.
Graphical Abstract A method is described for the determination of the activity of DNase I. It is based on the capability of nucleoside monophosphates (dNMPs; formed by DNase-catalyzed scission of dsDNA) to stabilize red gold NPs against NaCl-induced aggregation. AuNPs stabilized with dsDNA, in contrast, readily aggregate in presence of NaCl to form blue clusters.
