Highly Efficient Multiple‐Labeling Probes for the Visualization of Enzyme Activities

• Published in: Chemistry : a European journal 2019-11, Vol.25 (61), p.13994-14002
• Main Authors: Song, Heng, Li, Yuyao, Chen, Yefeng, Xue, Chenghong, Xie, Hexin
• Format: Article
• Language: English
• Subjects: Alkaline phosphatase; Alkaline Phosphatase - chemistry; Alkaline Phosphatase - metabolism; Animals; Chemistry; Efficiency; Enzymatic activity; enzyme activity; Fluorescent Dyes - chemistry; HEK293 Cells; HeLa Cells; Humans; imaging; Immobilization; Indolequinones - chemistry; Indolequinones - metabolism; Labeling; Mice; Mice, Nude; Microscopy, Fluorescence; Optical Imaging; Probes; quinone methide; Quinones; Reagents; Staining and Labeling; Transplantation, Heterologous; Trapping; Visualization
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201903458

Quinone methide (QM) as a latent trapping unit has been widely explored in activity‐based self‐immobilizing reagents. However, further application of this strategy has been largely hampered by the limited labeling efficiency to proteins. In this study, a thorough investigation on the labeling efficiency and the structure of QM‐based trapping unit is presented, from which a QM with multiple leaving groups was identified as an optimal trapping unit. An alkaline phosphatase (ALP) immobilizing reagent featured with this multiple‐labeling trapping unit exhibited lower nonspecific binding and, remarkably, a significantly higher labeling efficiency over other immobilizing reagents upon enzymatic activation. The utility of this imaging reagent was further demonstrated with the in vitro and in vivo visualization of the ALP activities. Furthermore, the multiple functional trapping unit may find greater value in the other activity‐based immobilizing probes. Visualizing the activity: An investigation on the labeling efficiency and structure of quinone methide (QM) based trapping unit is presented, from which a QM with multiple leaving groups was identified as an optimal trapping unit. An alkaline phosphatase (ALP) immobilizing reagent featured with this multiple‐labeling trapping unit exhibited upon enzymatic activation a lower nonspecific binding and, remarkably, a significantly higher labeling efficiency over other immobilizing reagents. In vitro and in vivo visualization of the ALP activity is also reported.