An Enzyme Cascade Strategy for Sensitive Detection of Acid Phosphatase / 分析化学

ABSTRACT

An enzyme cascade strategy was introduced for sensitive detection of acid phosphatase ( ACP) . Pyrophosphate ions ( PPi ) can strongly bound Fe3+and thus hinders the production of Prussian blue nanoparticles (PBNPs). ACP can hydrolyze PPi to form phosphate ions, and the released Fe3+reacts with potassium ferrocyanide ( K4[ Fe ( CN )6] ) to form PBNPs. The formed PBNPs have high peroxidase-like activity, which can decompose hydrogen peroxide ( H2O2) to produce hydroxyl radical (·OH) for oxidizing the typical substrate of 3,3′,5,5′-tetramethylbenzidine ( TMB). Therefore, a novel sensing strategy for detecting ACP based on the high signal amplification of enzyme cascade was constructed. The results showed that there was a good linear relationship between the absorbance of oxidized TMB ( oxTMB ) and the concentration of ACP in the range of 3-20 U/L, with a detection limit of 0. 8 U/L. Different from the conventional enzyme cascades in which the product of one enzyme is the substrate of the other, this study opens up a new way to construct novel enzyme cascade system.