Alkaline phosphatase composition, method of producing dephosphorylated nucleic acid and method of producing labeled nucleic acid

A composition comprising:

• an alkaline phosphatase;
• a first peptide fragment consisting of the amino acid sequence set forth in SEQ ID NO:
• 1;
• a second peptide fragment consisting of the amino acid sequence set forth in SEQ ID NO:
• 2;
• a third peptide fragment consisting of the amino acid sequence set forth in SEQ ID NO:
• 3;
• a fourth peptide fragment consisting of the amino acid sequence set forth in SEQ ID NO:
• 4;
• a fifth peptide fragment consisting of the amino acid sequence set forth in SEQ ID NO:
• 5;
• and
• a sixth peptide fragment consisting of the amino acid sequence set forth in SEQ ID NO:
• 6,
• wherein content ratios of the first to sixth peptide fragments to the alkaline phosphatase satisfy formulas (1) to (6), respectively:
• (X1/Y)×100≤0.6000 (1);
• (X2/Y)×100≤0.1800 (2);
• (X3/Y)×100≤0.2000 (3);
• (X4/Y)×100≤0.8000 (4);
• (X5/Y)×100≤1.6000 (5);
• and
• (X6/Y)×100≤0.3500 (6),
• wherein X1 to X6 represent peak area values of the first to sixth peptide fragments calculated by an automatic integration method from an extracted ion chromatogram obtained by an LC-MS/MS analysis of the composition, respectively, and Y represents a peak area value of the alkaline phosphatase calculated by an automatic integration method from a chromatogram obtained by an LC-UV analysis of the composition.