ThisadvancedbiotinylationreagentcontainsUV-traceablebenzophenonemoietythathasabsorptionmaximumat350nm.Twosurroundedhydrophilicarmsenhancewatersolubility,reducethetendencyofsomeproteinstoaggregate/precipitateduringbiotinylation,andimproveconjugateyieldatmoderately-to-higherbiotinloads.Afterbiotinylation,theconjugate’sabsorbanceat280nmand350nmisusedtorapidlyandquantitativelymeasurethelevelofbiotinincorporation.UV-TracerTMBiotin-Maleimidereagentimproveslabelingreproducibilityandyieldathigherbiotinloadsformaximumassaysensitivityandrobustness.