Table II.
Substrate oxidation by mitochondrial fractions from germinating maize embryos
| Substrate | Rate of Oxygen Uptake in fraction
|
|||||
|---|---|---|---|---|---|---|
| Light mitochondria
|
Heavy mitochondria
|
|||||
| 0 h of imbibition | 6 h of imbibition | 48 h of imbibition | 0 h of imbibition | 6 h of imbibition | 48 h of imbibition | |
| nmol min−1 mg−1 protein | ||||||
| NADH | 9 ± 2 | 25 ± 3 | 25 ± 1 | 24 ± 3 | 54 ± 6 | 72 ± 5 |
| NADH + cytochrome c | 39 ± 4 | 45 ± 8 | 38 ± 2 | 123 ± 9 | 131 ± 16 | 78 ± 4 |
| Succinate | 3 ± 1 | 2 ± 1 | 5 ± 1 | 7 ± 3 | 19 ± 1 | 46 ± 3 |
| Outer membrane intactness (%) | 69 ± 5 | 62 ± 5 | 81 ± 3 | 66 ± 6 | 84 ± 3 | 93 ± 1 |
Rates of O2 consumption were measured in the presence of NADH (1mm) or succinate (m) + ATP (0.1 mm) following the addition of a saturating amount of ADP. Where indicated, cytochrome c (50 μm) was added before addition of ADP. Outer membrane integrity was measured as the latency of cytochome c oxidase activity using Triton X-100 (0.05% [w/v]) to obtain maximal activity. Values represent the means of three separate experiments ± se.