The ubiquitin molecule is bound to a quenched fluorophore (e.g. Rhodamine 110). After DUB digestion the fluorophore is freed and is detected by the plate reader. This simple and straight-forward assay is a great high-throughput option for most DUBs. LifeSensors has years of experience working with different DUB families, contact us for a free consultation to select the right assay for your specific project.