The activity of beta-galactosidase from Escherichia coli was characterized by scanning electrochemical microscopy (SECM). beta-Galactosidase microspots were patterned by immobilizing biotin-labelled beta-galactosidase on streptavidin-coated paramagnetic beads and depositing the beads as microscopic microspots on a hydrophobic surface. The enzyme activity was mapped with SECM in the gene ration-collection mode by monitoring the oxidation of p-aminophenol formed in the galactosidase-catalyzed hydrolysis at the surface of the beads. The electrochemical properties of the enzyme substrate and product were studied with a platinum ultramicroelectrode, and the imaging conditions were optimised. The suitability of the procedure for forming beta-galactosidase microspot arrays and the capability of SECM to resolve enzyme activity over individual enzyme microspots were demonstrated. (C) 2003 Elsevier B.V. All rights reserved.
Zhao, C., Sinha, J. K., Wijayawardhana, C. A., & Wittstock, G. (2004). Monitoring beta-galactosidase activity by means of scanning electrochemical microscopy. Journal of Electroanalytical Chemistry, 561, 83 - 91. https://doi.org/10.1016/j.jelechem.2003.07.004