PLCP activity and expression in different organs and in vivo. A, Activity profiles of PLCPs of different organs. Crude extracts of various organs were labeled with 2 μm DCG-04, either with or without a 30-min pretreatment with E-64 (10 μm), for 2.5 h at pH 6. Biotinylated proteins were detected on protein blots using streptavidin-horseradish peroxidase. CBB, Coomassie Brilliant Blue. B, Spectral counts of labeled PLCPs detected in different organs. Extracts from various organs were labeled with MV202 at pH 6, and labeled proteins were purified on avidin beads, separated on protein gels, excised, digested with trypsin, and analyzed by LC-MS/MS. The spectrum of peptides with greater than 95% confidence was counted for each PLCP; these are summarized in Supplemental Table S1. C, Transcript levels of all PLCPs in different organs. These data were extracted from Genevestigator (). D, In vivo labeling of PLCPs reveals activities of RD19A and RD19B. Arabidopsis cell cultures were labeled with 5 μm MV201. Proteins were extracted and coupled to Bio≡ using click chemistry. Biotinylated proteins were purified on avidin beads, separated on denaturing acrylamide gels, excised, digested with trypsin, and analyzed by LC-MS/MS. The spectrum of peptides with greater than 95% confidence was counted for each PLCP. [See online article for color version of this figure.]