A highly selective and sensitive near-infrared fluorescence probe for arylamine N-acetyltransferase 2 in vitro and in vivo

We developed a near-infrared fluorescence probe for the highly selective and sensitive detection of NAT2 activity. An arylamine was designed as the substrate part for NATs, as well as a PET quencher for cyanine dye. CYP1 with a 4-position arylamine displayed efficient PET quenching, and exhibited high selectivity and sensitivity to NAT2 with no response to NAT1. For practical application, we demonstrated CYP1 could exhibit excellent performance for endogenous NAT2 fluorescence imaging in living mice. We further verified the NAT2 distribution in various tissues by detecting the response to the corresponding tissue homogenates. The results were consistent with the fluorescence imaging in vivo and previous research. Above all, the probe CYP1 could selectively and sensitively monitor the NAT2 activity in enzymatic system, living mice and tissue homogenate samples. Therefore, the results indicated that CYP1 has potential use for the detection of NAT2 activity in the clinic and in research.