A novel fluorogenic substrate for dinuclear Zn(II)-containing metallo-β-lactamases

Article abstract of DOI:10.1016/j.bmcl.2013.01.071

In an effort to prepare a fluorogenic substrate to be used in activity assays with metallo-β-lactamases, (6R,7R)-8-oxo-7-(2-oxo-2H-chromene-3- carboxamido)-3-((4-(2-oxo-2H-chromene-3-carboxamido)-phenylthio)methyl) -5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid (CA) was synthesized and characterized. CA exhibited a fluorescence quantum yield (φ) of 0.0059, two fluorescence lifetimes of 3.63 × 10^-10 and 5.38 × 10 ^-9 s, and fluorescence intensity that is concentration-dependent. Steady-state kinetic assays revealed that CA is a substrate for metallo-β-lactamases (MβLs) L1 and CcrA, exhibiting K_m and k_cat values of 18 μM and 5 s^-1 and 11 μM and 17 s^-1, respectively.