Hydrolases, enzymes that catalyze the hydrolysis of a covalent bond, are important molecules that are involved in various biological functions. Like other biomolecules, hydrolase activities are tightly regulated in healthy or diseased states. By detecting or imaging the activities of hydrolases using molecular imaging probes, we can reveal the underlying molecular mechanisms in the context of cells to organisms. Furthermore, their correlation with different physiological conditions can therefore be used in diagnosis. Due to the nature of hydrolases, substrate-based probes can be activated in their catalytic cycles, and cleavage of covalent bonds frees reporter moieties. For test-tube type bulk detection, spatial resolution is not a measure of importance, however, for cell- or organism-based detection or imaging, spatial resolution is a key factor for probe sensitivity that influences signal-to-background ratio. One strategy to improve spatial resolution of the probes is to form a covalent linkage between the reporter moiety and intracellular proteins upon probe activation by the enzyme. In this work, we have synthesized and compared various quinone methide structures with tunable functional groups. These probes contain different leaving groups that can influence the electronics of the aromatic ring for β-galactosidase activation, as well as the reactivity of quinone methide species. The labeling efficacy of these probes were evaluated using gel electrophoresis as well as live cell fluorescence microscopy and flow cytometry. This study provides an insight into applying quinone methide chemistry in the development of hydrolase-targeting probes for cell- or organism-based imaging.

Tuning the efficiency of molecular probes via enhanced in situ labeling

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.