Voltammetric lipase activity assay based on dilinolein and a modified carbon paste electrode

Abstract

In this work, a novel electrochemical assay for characterizing both lipases and lipase inhibitors as well as for the determination of lipase activity is described. It is based on a carbon paste electrode, modified with cobalt(II)phthalocyanine, and multi-walled carbon nanotubes (MWCNTs). As reaction media, a sodium borate buffer was used (0.1 M, pH 9). The measurements were carried out in a batch system using differential pulse voltammetry (DPV) and 1,3-dilinolein as standard substrate. The activity assay showed a linearity for porcine pancreas lipase activity in a range between 20 and 300 U L−1 (per min) with a limit of detection (LOD) of 7 U L−1 and a limit of quantification (LOQ) of 20 U L−1. The kinetic behavior of the lipase reaction was investigated, resulting in a KM value of 0.29 mM. The applicability of the activity assay could be shown by investigating the activity of lipases from Aspergillus oryzae and Candida rugosa, and the results were confirmed by a reference method. The inhibitory effects were characterized with Orlistat. Graphical abstract

Sensing of Digestive Enzymes—Diagnosis and Monitoring of Pancreatitis

“…The substrate was glycerol linoleate, and the enzymatic reaction of lipase formed linoleic acid (LA). The reductive LA is oxidized on the electrode surface, which in turn can be detected by cyclic voltammetry [238]. Sample preparation, the flow system, and electrochemical conditions were optimized by Sarakhman et al [239].…”