Sensitive biosensor based on recombinant PP1α for microcystin detection.

A novel electrochemical microcystin-LR (MC-LR) biosensor based on the inhibition of recombinant protein phosphate type 1 (PP1α) is reported in this work. The use of innovative recombinant enzyme led to investigate new commercially available substrate, electrochemically active after their dephosphorylation by PP1α. Only two of selected substrates, 1-naphylphosphate and phosphoparacetamol, showed a good affinity toward PP1α. Kinetic parameters were performed by classical colorimetric assays and revealed that phosphoparacetamol is an excellent synthetic substrate with a Km value of 1.2 mM. The reported biosensor is constructed by entrapment of the enzyme in Polyvinyl Alcohol (azid unit) on Cobalt-Phtalocyanine (CoPC) modified screen printed electrode. Electrocatalytic mediator demonstrated a significant improvement in the electrochemical detection of dephosphorylated substrate. The standard inhibition curve has provided a limit of detection at 0.93 µg/L and a broad dynamic range from 0.93 to 40.32 μg/L for MC-LR, demonstrating the improved analytical performance.