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. Author manuscript; available in PMC: 2007 Jun 15.
Published in final edited form as: Anal Biochem. 2006 Mar 31;353(2):209–216. doi: 10.1016/j.ab.2006.03.020

Figure 1.

Figure 1

Schematic diagram of the solid-phase nanoparticle release assay. (A) A 232 base pair DNA fragment containing single restriction enzyme sites is generated by PCR from a plasmid using primers that are modified with either a 5′ primary amine or biotin. The EcoR1 and Xba1 sites are 114 and 149 base pairs, respectively, from the 5′ amine substrate immobilization site. (B) PRPs are used to label covalently immobilized DNA fragments and enzymatic activity is detected by measuring the release of the tethered PRP during the reaction. Site specific methyltransferase activity modifies the substrate resulting in a non-cleavable substrate, inhibiting enzyme digestion and limiting PRP release.