Detecting immobilized protein kinase C isozymes with RNA aptamers

Nucleic acids that can bind tightly and specifically to protein targets can be selected from random sequence pools. Just as antibodies have been used to detect proteins in a variety of formats, it is possible the nucleic acid binding species (aptamers) could be used to specifically detect proteins. Using a simple filter binding assay, aptamers have been used to detect protein kinase C (PKC) introduced into a cell extract. Aptamers that were relatively nonspecific could be used to simultaneously detect different PKC isozymes, while aptamers with higher specificities could discriminate between related isozymes. These results demonstrate the feasibility of using aptamers as diagnostic tools to detect proteins.