BIOASSAY USING A LABELED OLIGONUCLEOTIDE OBTAINED BY IN-VITRO SELECTION

A new bioassay system using an oligodeoxyribonucleotide (DNA) obtained by the in vitro selection method is described. The DNA aptamer which selectively binds to a target molecule, Reactive Green 19 (RG19), was labeled with fluorescein. The circular dichroism spectra revealed that the fluorescein labeling did not significantly affect the conformatio n of the DNA. The binding affinity toward RG19 of the labeled DNA was the same as that of the nonlabeled DNA. Using the labeled DNA and the RG19-immobilized gel, a semiquantitative assay of RG19 concentration w as performed.