Electrochemical Detection of Fucosidase Activity in Human Serum

Liver cancer is one of the most common malignant tumors globally and is the second leading cause of cancer deaths in Taiwan. The activity of alpha-fucosidase (AFU) in the human body has been confirmed by many clinical studies and experiments to be applicable in the early diagnosis of primary liver cancer. Herein, an electrochemical method for determining AFU activity was developed based on measuring p-nitrophenol (pNP), which is a product of the reaction between AFU and p-nitrophenyl-alpha-L-fucopyranoside. The electrochemical detection of pNP in serum samples exhibited a wide linear range (2.5-250 mu M), which corresponds to approximately 2.5-250 U/L AFU. The recovery of AFU measured upon enzyme addition to standard serum was 97-110%. Moreover, no potential interferants had a significant effect on pNP quantification. In contrast, an optical absorption method was subject to interference by the serum color. Further, the linear range for pNP was only 2.5-50 mu M and the recovery of AFU was 165-219%. The performance of this absorption method could lead to a misjudgment of the disease course. Therefore, the electrochemical method for AFU activity determination has greater potential for use in clinical applications.