Abstract
Arsenic (As) pollution is a widespread problem worldwide. In recent years, biosensors based on enzymatic inhibition have been developed for arsenic detection, making the study of the effect of inhibitors on the selected enzymatic activity crucial for their setup. The arsenate reductase of Thermus thermophilus HB27, TtArsC, reduces As(V) into As(III), but is also endowed with phosphatase activity. This work investigates the inhibitory effects of As(V) and As(III) on phosphatase activity by taking advantage of a simple colorimetric assay; the results show that both of them are non-competitive inhibitors affecting the Vmax but not the KM of the reaction. However, their Ki values are different from each other (15.2 ± 1.6 μM for As(V) and 394.4 ± 40.3 µm with As(III)), indicating a higher inhibitory effect by As(V). Moreover, the inhibition-based biosystem results to be selective for As(V) since several other metal ions and salts do not affect TtArsC phosphatase activity; it exhibits a sensitivity of 0.53 ± 0.03 mU/mg/μM and a limit of detection (LOD) of 0.28 ± 0.02 μM. The good sensitivity and specificity for As(V) point to consider inhibition of TtArsC phosphatase activity for the setup of a novel biosensor for the detection of As(V).
Highlights
Arsenic is a toxic metalloid, commonly occurring as a groundwater pollutant
We investigate the inhibitory effect of arsenic on TtArsC phosphatase activity to evaluate its exploitation as an optical biosensor
To verify the potential employment of the enzyme as an optical biosensor to detect arsenic, we investigated the effects of arsenic and other metal ions on TtArsC phosphatase activity
Summary
Arsenic is a toxic metalloid, commonly occurring as a groundwater pollutant. It largely derives from mines, industrial wastes, or geochemical processes, and both its organic and inorganic forms can be found in the environment [1]. Arsenic is one of WHO’s 10 chemicals of major public health concern; millions of people all over the world are exposed to arsenic concentrations much higher than the guideline value (10 μg/L in drinking water), and the effects of long-term exposures at toxic concentrations are the cause of many diseases that, in extreme cases, lead to death [4]. For these reasons, in the 2030 Agenda for Sustainable Development, the indicator of “safely managed drinking water services” aims to guarantee all people access to drinking water free of microbial and chemical contaminants, including arsenic, which must be monitored [3,7–9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
