Merck, C5896-1KU, Choline Oxidase from Alcaligenes sp.

General description
Isoelectric point:4.1 ± 0.1
Michaelis constants:2.84 x 10¯³M (Choline), 5.33 x 10¯³M (Betaine aldehyde)
Structure:One mol of FAD is covalently bound to mol of the enzyme
Inhibitors:p-Chloromercuribenzoate, Cu⁺⁺, Co⁺⁺, Hg⁺⁺, Ag⁺
Optimum pH:8.0 – 8.5
Optimum temp:40 – 45°C
pH Stability:pH 7.0 – 9.0 (30°C, 2hr)
Thermal stability:Below 37°C (pH 7.5, 10min)
Application
Choline oxidase from Alcaligenes sp. has been used: in a study to investigate a choline biosensor constructed with a chitinous membrane and its application in measuring cholinesterase inhibitory activities
has also been used in spectroscopic studies on the photoreaction of choline oxidase with covalently bound flavin.
as a component of phosphate buffer saline (PBS) buffer for measurement of choline acetyltransferase (ChAT) activity in brain tissue homogenates
to measure the choline generated by autotaxin (ATX) by ATX activity assay and phospholipase-D (PLD) by PLD activity assay

Biochem/physiol Actions
Choline oxidase catalyzes the four-electron oxidation of choline to glycine-betaine, with betaine-aldehyde as the intermediate and molecular oxygen as th eprimary electron acceptor. The enzyme can also accept betaine-aldehyde as a substrate. This allows the study of the reaction mechanism for the conversion of choline to the aldehyde intermediate, & of betaine-aldehyde to glycine-betaine. The enzyme is a flavoprotein with a molecular weight of approx. 72,000 Da (gel filtration) or 66,000 Da (SDS gel electrophoresis).
Other Notes
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.