Figure 3.

TPI Activity Was Reduced and Metabolic Intermediate Pools Were Altered in the pdtpi Mutant.

Plants were germinated on MS agar plates under continuous light for 5 d, and shoots were harvested for activity assays in solution (B) and in native gels (C) and for immunoblotting (D) and metabolite analysis (E). Values were determined to be significantly different by t test with P values of 0.02 in (B) and 0.03, 0.03, 0.04, and 0.04 in (E) for glycerol, G-3-P, DHAP, and GAP, respectively.

(A) Full-length (pdTPI) and N-terminal truncated ( Δ pdTPI) proteins were expressed and purified from E. coli as activity assay controls.

(B) TPI activity in the wild type (Col) and pdtpi mutant.

(C) TPI activity staining in PAGE gel under nondenaturing conditions. Native Δ pdTPI recombinant protein was loaded as a control.

(D) Isoelectric immunoblotting with anti-cytoTPI antibody. Twenty micrograms of total protein was loaded per lane. Plastid and cytosolic TPI bands are noted.

(E) Quantification of metabolites in wild type (Col; open bars) and pdtpi mutant (closed bars). Four biological replicates were used for TPI activity assay and metabolite quantification in the wild type and mutant; data are presented as the mean ± se.