Method for stabilizing ascorbic acid oxidase

1. A method for stabilizing an ascorbic acid oxidase, which comprises allowing the ascorbic acid oxidase to coexist at −5 to 45° C. for at least 10 days with nitrous acid or a salt thereof, or a nitrous acid ester in an aqueous medium, wherein

the salt is selected from the group consisting of a lithium salt, a sodium salt, a potassium salt, an ammonium salt, a calcium salt and a magnesium salt, and

the nitrous acid ester is selected from the group consisting of methyl nitrite, ethyl nitrite, propyl nitrite, butyl nitrite, pentyl nitrite and isopentyl nitrite.

2. A method for preserving an ascorbic acid oxidase, which comprises allowing the ascorbic acid oxidase to coexist at −5 to 45° C. for at least 10 days with nitrous acid or a salt thereof, or a nitrous acid ester in an aqueous medium, wherein

the salt is selected from the group consisting of a lithium salt, a sodium salt, a potassium salt, an ammonium salt, a calcium salt and a magnesium salt, and

the nitrous acid ester is selected from the group consisting of methyl nitrite, ethyl nitrite, propyl nitrite, butyl nitrite, pentyl nitrite and isopentyl nitrite.