A novel biotinylated adenylate analogue derived from pyrazolo[3,4-d]pyrimidine for labeling DNA probes.

A novel dATP analogue, 3-5-(N-biotinyl-6- amiocaproyl)amino]pentyl]-1-(2-deoxy-beta-D-erythro-pentofuranosyl )-1H-pyrazolo3,4-d]pyrimidin-4-amine 5'-triphosphate (9, bio-13-dAPPTP), which is modified at the 3-position with a flexible linker arm bearing a terminal biotin moiety, has been synthesized. This nucleotide is readily incorporated into DNA probes by nick translation. These probes hybridize to complementary targets as well as probes labeled with bio-dUTP, as judged by slot blot. When incorporated into oligonucleotides, they do not cause the loss of hybridization efficiency that an N-6-substituted adenine nucleotide does when incorporated into the same sites in the oligonucleotide.