Patent ID: 8080649

Claim:
An aptamer possessing an inhibitory activity against midkine, which is either (a) or (b) below: (a) an aptamer comprising a nucleotide sequence selected from SEQ ID NOs: 20 and 67 (with the provision that the uracil may be thymine), wherein the nucleotides contained in the aptamer are such that, (i) the 2′-positions of the pyrimidine nucleotides, whether identical or different, are fluorine atoms or substituted by atoms or groups selected from the group consisting of hydrogen atoms, hydroxy groups and methoxy groups, and (ii) the 2′-positions of the purine nucleotides, whether identical or different, are hydroxy groups or substituted by atoms or groups selected from the group consisting of hydrogen atoms, methoxy groups and fluorine atoms; (b) an aptamer comprising a nucleotide sequence selected from SEQ ID NOs: 20 and 67 (with the provision that the uracil may be thymine), wherein one to three nucleotides are substituted, deleted, inserted or added, wherein the nucleotides contained in the aptamer are such that, (i) the 2′-positions of the pyrimidine nucleotides, whether identical or different, are fluorine atoms or substituted by atoms or groups selected from the group consisting of hydrogen atoms, hydroxy groups and methoxy groups, and (ii) the 2′-positions of the purine nucleotides, whether identical or different, are hydroxy groups or substituted by atoms or groups selected from the group consisting of hydrogen atoms, methoxy groups and fluorine atoms.