Choline oxidase from Sigma has been used in the enzymatic determination of choline in milk using a flow injection analysis (FIA) system with potentiometric detection.
Choline oxidase from Alcaligenes sp. has been used in a study to investigate a choline biosensor constructed with chitinous membrane and its application in measuring cholinesterase inhibitory activities. Choline oxidase from Alcaligenes sp. has also been used in spectroscopic studies on the photoreaction of choline oxidase with covalently bound flavin.
Choline oxidase catalyzes the four-electron oxidation of choline to glycine-betaine, with betaine-aldehyde as intermediate and molecular oxygen as primary electron acceptor. The enzyme can also accept betaine-aldehyde as a substrate. This allows the investigation of the reaction mechanism for the conversion of choline to the aldehyde intermediate and of betaine-aldehyde to glycine-betaine. The enzyme is a flavoprotein with a molecular weight of approximately 83,000 Da according to gel filtration or approximately 71,000 Da according to SDS gel electrophoresis. The optimum pH is found to be around pH 7.5 and the isoelectric point (pI) around pH 4.5.
