Figure 1.

Competitive inhibition of the fluorescent substrate by gelatin. Gelatin inhibition of 3 nM FAP enzymatic activity was performed by incubating serial dilutions of gelatin in reaction buffer prior to the addition of the fluorescent substrate Ala-Pro-AFC. Nearly 75% inhibition of FAP DPP activity can be seen. Thus, gelatin competitively attenuates cleavage of the fluorescent Ala-Pro-AFC substrate by recombinant FAP.