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Updated: Jan 22, 2026

Mapping Metabolism: Monitoring Lactate Dehydrogenase Activity Directly in Tissue
Published on: June 21, 2018
A hydrophobin-based-biosensor layered by an immobilized lactate dehydrogenase enzyme for electrochemical
Fatemeh Mirzaei1, Mohammad Mirzaei2, Masoud Torkzadeh-Mahani3
1Department of Chemistry, Shahid Bahonar University of Kerman, Kerman, Iran; Young Research Society, Shahid Bahonar University of Kerman, Kerman, Iran.
Abstract:
Appropriate enzyme immobilization on the electrode surface in order to access its active site has always been an important strategy for electrode modification. In this report, lactate dehydrogenase enzyme was appropriately immobilized on the glassy carbon electrode via hydrophobin (HFB1) and graphene oxide nanocomposite. The step-by-step modification was successfully confirmed by water contact analysis, cyclic voltammetry, and electrochemical impedance spectroscopy. Under optimum conditions, this biosensor demonstrated a detection limit of 8.69 nM and RSD of 4.3% and 3.6% (n = 5) for reproducibility and repeatability. The effect of scan rate on the oxidation behavior of NADH was investigated by cyclic voltammetry; and diffusion coefficient for NADH was estimated at 6.27 × 10-8 cm2.s-1. The apparent Michaelis-Menten constant (Kmapp) was amperometrically determined and it was lower than Kmapp for the free enzyme. Also, the modified electrode represented good stability after nine days with 6% decrease in current. The proposed assay was successfully used in real sample-serum-analysis and the obtained recoveries were between 93% and 104.0%.
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