Method for separating biotinylated nucleic acid

A method for separating a biotinylated nucleic acid to which a nucleic acid-binding protein is bound, comprising the following steps:

• (1) a step for contacting a sample containing a protein capable of binding to a nucleic acid (a nucleic acid-binding protein), a biotinylated nucleic acid wherein the biotin is bound to the nucleic acid, and a tamavidin-immobilized insoluble carrier to form a complex of the nucleic acid-binding protein, the biotinylated nucleic acid, and the tamavidin-immobilized insoluble carrier (step B-1),
• (2) a step for separating the biotinylated nucleic acid to which the nucleic acid-binding protein is bound from the complex obtained in the step B-1, in a solution having pH of 7.8 to 9.5, and in the presence of free biotin (step B-2).

A method for separating a nucleic acid-binding protein, comprising the following steps:

• (1) a step for contacting a sample containing a nucleic acid-binding protein, a biotinylated nucleic acid wherein the biotin is bound to the nucleic acid, and a tamavidin-immobilized insoluble carrier to form a complex of the nucleic acid-binding protein, the biotinylated nucleic acid, and the tamavidin-immobilized insoluble carrier (step C-1),
• (2) a step for separating the biotinylated nucleic acid to which the nucleic acid-binding protein is bound from the complex obtained in the step C-1, in a solution having pH of 7.8 to 9.5, and in the presence of free biotin (step C-2),
• (3) a step for separating the nucleic acid-binding protein from the biotinylated nucleic acid to which the nucleic acid-binding protein is bound obtained in the step C-2 (step C-3).

A kit for separating a nucleic acid, comprising a reagent containing an insoluble carrier on which tamavidin is immobilized, and a reagent which makes pH of the solution after mixing in 7.8 to 9.5, as constituent reagents.