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 (PP1 alpha) is reported in this work. The use of innovative recombinant enzyme led to investigate new commercially available substrate, electrochemically active after their dephosphorylation by PP1 alpha. Only two of selected substrates, 1-naphylphosphate and phosphoparacetamol, showed a good affinity toward PP1 alpha. Kinetic parameters were performed by classical colorimetric assays and revealed that phosphoparacetamol is an excellent synthetic substrate with a K-m. 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 mu g/L and a broad dynamic range from 0.93 to 40.32 mu g/L for MC-LR, demonstrating the improved analytical performance. (C) 2014 Elsevier B.V. All rights reserved.