Merck, A0157-1KU, Ascorbate Oxidase from Cucurbita sp.

General description
Ascorbate oxidase is a homodimeric enzyme, which comprises 552 amino acid residues per subunit (zucchini). It corresponds to a molecular mass of 70kDa per subunit. This enzyme is mainly found in plants, fungi and eubacteria.
Application
Ascorbate Oxidase from Cucurbita sp. has been used:
as a supplement in the culture medium for differentiation into osteoblasts
to oxidize ascorbic acid producing monodehydroascorbate in monodehydroascorbate reductase assay
in determining ascorbate (AsA) and dehydroascorbate (DHA) concentrations

Ascorbate oxidase, from Cucurbita sp., may be used to study oxidative stress and heat stress response and tolerance. Ascorbate oxidase, from Sigma, has been used in ascorbic acid assays to study the heat stress response of Arabidopsis .
Biochem/physiol Actions
Ascorbate oxidase (AO) participates in cell growth by regulating reduction/oxidation (redox) of the apoplast. This enzyme can synthesize the oxidative molecule dehydroascorbate acid (DHA) in the apoplast. It is also involved in cell elongation and enlargement development.
Ascorbate oxidase converts ascorbic acid to dehydroascorbic acid. It is highly specific for L-ascorbic acid and a few analogs. Ascorbate oxidase exists as a dimer and has a molecular weight of approximately 140 kDa.
Physical form
Lyophilized powder containing buffers and sucrose as stabilizer.
Other Notes
One unit will oxidize 1.0 μmole of L-ascorbate to dehydroascorbate per min at pH 5.6 at 25 °C.