apf

APF is an aromatic amino-fluorescein derivative that serves as a highly specific fluorescent probe for detecting highly reactive radicals, exhibiting low intrinsic fluorescence but converting into strongly fluorescent fluorescein upon oxidation by hydroxyl radicals, hypochlorite ions, and selected peroxidase intermediates. APF remain unreactive to nitric oxide and hydrogen peroxide, while with fluorescein displays excitation and emission maxima of 490 nm and 515 nm, respectively, enabling sensitive visualization of oxidative stress in biological systems.

Suc-AAPF-pNA (Suc-Ala-Ala-Pro-Phe-pNA) is a substrate chromogen that releases a yellow 4-nitroaniline upon cleavage and is a substrate for many proteases and prostate-specific antigens (PAs), and can be used to identify novel protein hydrolytic activities in yeast mutants.