Choline Oxidase from Arthrobacter globiformis

Choline Oxidase from Arthrobacter globiformis has been used:

• for enzymatic determination of choline (Cho) and phosphocholine (P-Cho)
• in sphingomyelin assay to determine the concentration of sphingomyelin by measuring free choline
• in enzyme coating for the fully-assembled recording device for electrochemical measurements

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 Arthrobacterglobiformis is suitable for the preparation of amperometric biosensors.

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.

Research area: Cell signaling. Choline oxidaseis a flavoprotein and belongs to the glucose methanol choline(GMC)-oxidoreductase family.

One unit will form 1 μmole of H₂O₂ with oxidation of 1 μmole of choline to betaine aldehyde per min at pH 8.0 at 37 °C. Note: During the conversion of choline to betaine by choline oxidase, 2 μmoles of H₂O₂ are produced for every μmole of choline.