Figure 6.

Proteolysis of N-LP-FRET substrate. The substrate was incubated with leaf extract at pH 5.5, and the reaction mixture was characterized by LC-MS. The fragments were separated by RP-HPLC and identified by ESI mass spectrometry. The RP-HPLC profiles of untreated N-LP-FRET (dashed line) and the reaction mixture (solid line) are compared. The bonds digested in N-LP-FRET (arrow, major fragmentation; arrowheads, minor fragmentation) and elution of the corresponding fragments are indicated by numbers. RP-HPLC was performed on a C₄ Vydac column equilibrated in 0.1% (v/v) TFA, eluted with an acetonitrile gradient (dotted line), and monitored by absorbance of DABCYL group.