LE 28 is a selective, activity-dependent probe for legumain that fluoresces exclusively upon binding to the active enzyme. It is applicable in research on cancers and inflammatory diseases [1].

LE 28 at concentrations ranging from 0 to 5 μM, when administered for 1 hour, can be detected in RAW cell lysates through cleavage and subsequent fluorescent SDS-PAGE tagging of legumain [1].

LE 28 (2 mg/kg, i.v.) induces a specific signal in mouse kidneys [1]. In the HCT-116 xenograft tumor model, the signal appears around the tumor at 30 minutes post-administration and reaches peak signal-to-noise ratio between the tumor and normal tissue at 7 hours [1].