Ascorbate oxidase, second cupredoxin domain (IPR034258)

Short name: CuRO_2_AAO

Overlapping homologous superfamilies


Domain relationships


Ascorbate oxidase catalyzes the oxidation of ascorbic acid to dehydroascorbic acid. This multicopper oxidase (MCO) is found in cucurbitaceous plants such as pumpkin, cucumber, and melon. It can detect levels of ascorbic acid and eliminate it. The biological function of ascorbate oxidase is still not clear [PMID: 23299329]; some studies suggest that it may play a crucial role in cell elongation and enlargement [PMID: 16652952]. In pumpkin, its expression is increased during callus growth, fruit development and seedling elongation [PMID: 16666364].

MCOs couple oxidation of substrates with reduction of dioxygen to water. Although MCOs have diverse functions, majority of them have three cupredoxin domain repeats that include one mononuclear and one trinuclear copper centre. The copper ions are bound in several sites: Type 1, Type 2, and/or Type 3. The ensemble of types 2 and 3 copper is called a trinuclear cluster. MCOs oxidize their substrate by accepting electrons at a mononuclear copper centre and transferring them to the active site trinuclear copper centre [PMID: 1548698]. The cupredoxin domain 2 of 3-domain MCOs has lost the ability to bind copper.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.