Sensitive chemiluminescence detection of prion protein on a membrane by using a peroxidase-labeled dextran probe.

We synthesized dextran-based macromolecular probes carrying multiple molecules of horseradish peroxidase (HRP) as a signal-trigger enzyme and of biotin as an assembly mediator without losing the enzymatic activity. Multiple attachments of HRP and biotin to the dextran backbone were readily accomplished after the formation of aldehyde groups into the dextran macromolecule by periodate oxidation. The synthesized macromolecular probe was successfully used for sensitive chemiluminescence (CL)-imaging detection of mouse recombinant prion protein on a nylon membrane. The prion protein at a small amount of 20 fmol blotted on a nylon membrane was specifically detected, indicating at least a 10-times higher sensitivity than that of a conventional biotinylated HRP probe. Therefore, the synthesized dextran-based probes containing HRP and biotin should be used for the sensitive high-throughput analysis of various proteins on a solid-phase membrane.