SP-13786 is a highly potent and selective inhibitor of fibroblast activation protein (FAP) with an IC50 of 3.2 nM and also inhibits prolyl oligopeptidase (PREP) with an IC50 of 1.8 μM.

CY2-SE is a dye for the labeling of amino-groups in peptides, proteins, and oligonucleotides.

Oroxylin A 7-O-beta-D-glucuronide, a natural product isolated and purified from the roots of Scutellaria regeliana Nakai., can bind to the "stem" region of α-hemolysin (α-HL), when inhibiting the hemolytic activity of α-HL, and inhibit 34% of total prolyl oligopeptidase (POP) activity, respectively at a concentration of 100 mM.

Y-29794 is a prolyl endopeptidase inhibitor with Ki value of 0.95nM for rat brain prolyl endopeptidase.