| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 807362 | Sensing and Bio-Sensing Research | 2016 | 6 Pages |
•A sensitive and low-cost fluorescence sensor for S1 assay at neutral pH was constructed.•This is the first systematic study about the activity assay and kinetics study of S1 at neutral pH.•The strategy has been successfully used to search partial effectors of S1 nuclease activity in vitro.
As the extracellular nuclease of Aspergillus, S1 nuclease can split single and double-stranded DNA into oligo- or mononucleotides, while preferentially digests single-stranded nucleic acids. Furthermore, the existence of S1 can be the standard to identify Aspergillus and used to evaluate the severity of Aspergillosis. Herein, a simple and sensitive fluorescent sensing platform for S1 assay was developed based on the S1-induced DNA strand scission and the difference in affinity of graphene oxide (GO) for single-stranded DNA containing different bases. This platform was applied to monitor S1 activity and study the kinetics in real time. Results indicated that the detection limit is 0.5 U/mL. The Km and kcat at 45 °C, are 1.4 ± 0.12 μM and 0.6 min− 1, respectively. Moreover, by monitoring the effect of chemical drugs on S1 activity, we found that 2 mM of erythromycin, sodium penicillin, carbenicillin disodium and ampicillin can inhibit S1 activity about 8%, 60%, 61% and 66%, respectively, while gentamycin sulfate is a stimulator. Overall, the assay platform based on graphene oxide quenched fluorescence probe is successfully constructed to study the enzymatic activity of S1 and used for screening antibiotics.
