Figure 4. FGF21 processing in plasma with FAP inhibitor or FAP immunodepleted.

(A) Structure of FAP inhibitor. (B) FGF21 was spiked into control plasma (ctrl), control plasma with FAP-specific inhibitor spiked-in (inhibitor), FAP immunodepleted plasma (depleted) or FAP immunodepleted plasma with exogenous FAP spiked in at 200 ng/ml (depleted+FAP). The samples were incubated at 37°C for 24 h, and FGF21 cleaved products were quantified using LC-MRM.