Novel High-Selectivity Fluorescent Probe for Detecting Alkaline Phosphatase Activity in Marine Environment

In marine environment, alkaline phosphatase (ALP) is a nonspecific phosphatase with metal ions as its active site. Metal ions have different effects on ALP activity. Therefore, a probe that specifically detects ALP needs to be developed. In this paper, to eliminate the interference of acid phosphatase, we designed and synthesized a highly selective fluorescent probe CyP based on pH to detect ALP activity. The response mechanism of detecting ALP was explained. The photophysical properties, enzyme kinetics, stability, selectivity, and potential quantitative ability of the probe under different pH values were investigated. The effects of metal ions on the ALP activity of marine Chlorella vulgaris and Escherichia coli were also analyzed. Excessive metal ions such as Zn²⁺, Cu²⁺, Hg²⁺, Pb²⁺, and Cd²⁺ inhibit while Mn²⁺, Co²⁺, and alkaline-earth metal ions promote the ALP activity of Chlorella and E. coli.