Fluorescent bioprobes for visualization of puromycin-sensitive aminopeptidase in living cells

Non-peptide, small-molecular, non-competitive inhibitors of puromycin-sensitive aminopeptidase (PSA), that is, 3-(2,6-diethylphenyl)-2,4(1H,3H)-quinazolinedione (PAQ-22, 3) and its 1N-methyl analogue (MPAQ-22 4), were structurally modified to afford fluorescent bioprobes, ANTAQ (5) and DAMPAQ-22 (6). The cellular localization of PSA could be visualized by the use of these fluorescent bioprobes.