Method for producing ketose using novel ketose-3-epimerase

The purpose of the present invention is to provide a method for producing psicose using a psicose-generating enzyme having high pH stability in a low pH region. The present invention is a method for producing psicose, which comprises a step in which a polypeptide is caused to act on fructose under acidic conditions of less than 6 in pH, the polypeptide is a polypeptide comprising the amino acid sequence represented by SEQ ID NO: 6 or a polypeptide having 90% or more sequence identity with the amino acid sequence represented by SEQ ID NO: 6, and having psicose-producing ability. 本发明的目的在于提供一种使用低pH区域的pH稳定性高的阿洛酮糖生成酶来制造阿洛酮糖的方法。本发明是一种阿洛酮糖的制造方法，其包含如下工序：使如下多肽在小于pH6的酸性条件下作用于果糖，所述多肽是由序列号6表示的氨基酸序列构成的多肽或与序列号6表示的氨基酸序列具有90％以上的序列同一性的多肽且具有阿洛酮糖生成能力的多肽。