Table II.

Respiration and SlGalLDH activity in isolated mitochondria from leaves

Respiration was measured in intact mitochondria prepared from young developing leaves of P35S:SlgalldhRNAi line 8, line 5, and control plants as described in the “Materials and Methods.” The reaction was conducted with 500 μg of mitochondria protein in 1 mL of respiration buffer in the presence of substrates at concentration as indicated. Prior to measuring the respiration in the presence of l-GalL, the mitochondria were incubated with 12.5 μm antimycine A. SlGalLDH activity was measured with 30 μg of mitochondrial protein as described in the “Materials and Methods.” Data represent mean ± sd of seven or eight individual mitochondrial isolations. Superscript a (a) indicates values that were determined by the t test to be significantly different (P < 0.01) from control.

RespirationControlLine 5Line 8
Electron Donor
nmol O2 min−1 mg−1 protein
2 mm NADH48.7 ± 5.546 ± 4.573.6 ± 3.7a
    + 2.5 mm ADP86.9 ± 8.475.8 ± 7.1139.9 ± 4.1a
    + 2 mm KCN10.4 ± 1.810.9 ± 3.820.6 ± 3.2a
    + 1 mm SHAM8.4 ± 2.59.6 ± 1.912.5 ± 2.1a
    Respiratory control1.781.651.90
5 mm succinate39.7 ± 7.848.4 ± 7.342.6 ± 10.9
    +2.5 mm ADP86.9 ± 1397.1 ± 12.895.2 ± 20.7
    Respiratory control2.192.002.23
5 mm Pyr/malate29.5 ± 4.534 ± 4.430.6 ± 3.4
    +2.5 mm ADP42.8 ± 8.347.6 ± 8.846.8 ± 4.6
    Respiratory control1.451.401.53
5 mm AsA39.9 ± 6.442.1 ± 5.139.7 ± 3.9
2.5 mm TMPD409.5 ± 32.5393.7 ± 44.3380.1 ± 45.4
4.2 mm l-GalL9.7 ± 0.95 ± 0.9a5.4 ± 0.6a
    +10 μm cytochrome c13.4 ± 1.66.9 ± 0.7a6.5 ± 0.8a
        SlGalLDH ActivityControlLine 5Line 8
nmol cytochrome c min−1 mg−1 protein
96 ± 15.149.6 ± 10.5a20 ± 5a