Fig. 2.

Activity assays and immunolocalization of chloroplastic Nicotiana tabacum Trx f and Trx m. (A) DTT-dependent insulin reduction assay of Trx f and Trx m. The assay was determined according to Holmgren (1979) in an incubation mixture containing 2 μM or 4 μM of Trx as indicated, supplemented with 0.5 mM DTT. Assays in the absence of Trx showing no activity were used as controls. (B) FBPase activation by Trx f and Trx m. FBPase activity was carried out according to Serrato et al. (2009). The incubation mixture contained a final concentration of FBPase 0.1 μM and increasing concentrations of Trxs as indicated. Each value is the mean ±SE (bars) of three independent determinations. (C, D) Immunogold labelling with anti- Trx f (C) and anti- Trx m (D) over different sections of a same chloroplast. Both figures exhibit specific labelling within the chloroplast (chl), in the form of dispersed particles. ct, Cytoplasm; cw, cell wall; s, starch; v, vacuole. Bars: 200 nm.