Table 2.
Platelet enzyme assays (nmol/min/mg) and SDS-PAGE analysis (OD). Statistical tests are Students 2-tailed t-tests, uncorrected for multiple comparisons, but with calculated P values shown. All subjects yielded Complex IV and III assay data; 1 MCI subject and 3 controls did not yield Complex I assay data. SDS-PAGE data for some bands were not available for some subjects; sample N for each is shown in parenthesis. A high outlier in the AD group skewed the SDS-PAGE OD means upward but was ameliorated by calculating the internal expression ratios of III and IV to I.
| Controls | MCI | AD | P: Ctl v. MCI | P: Ctl v. AD | |
|---|---|---|---|---|---|
| Assays: | |||||
| Complex IV | 114.4 ± 30.0 | 63.1 ± 38.6 | 72.0 ± 29.1 | 0.026 | 0.016 |
| Complex III | 131.1 ± 28.4 | 101.0 ± 31.2 | 80.2 ± 24.4 | 0.112 | 0.002 |
| Complex I | 50.2 ± 24.2 | 58.0 ± 29.2 | 49.8 ± 17.4 | 0.682 | 0.975 |
| Protein (μg/μl) | 1.4 ± 0.3 | 1.3 ± 0.5 | 1.4 ± 0.2 | 0.684 | 0.908 |
| SDS-PAGE: | |||||
| Complex IV | 0.156 ± 0.035 (5) | 0.077 ± 0.046 (3) | 0.171 ± 0.124 (6) | 0.031 | 0.798 |
| Complex III | 0.050 ± 0.033 (5) | 0.022 ± 0.016 (3) | 0.056 ± 0.053 (5) | 0.312 | 0.848 |
| Complex II | 0.029 ± 0.022 (5) | 0.022 (1) | 0.075 ± 0.144 (6) | 0.779 | 0.507 |
| Complex I | 0.094 ± 0.070 (5) | 0.051 ± 0.050 (3) | 0.105 ± 0.109 (6) | 0.397 | 0.849 |
| ATPase (V) | 0.280 ± 0.061 (5) | 0.202 ± 0.087 (3) | 0.264 ± 0.106 (6) | 0.183 | 0.777 |
| Ratio IV:I | 2.41 ± 1.54 (5) | 1.96 ± 1.16 (3) | 2.26 ± 1.29 (6) | 0.683 | 0.867 |
| Ratio III:I | 0.75 ± 0.87 (5) | 0.38 ± 0.11 (2) | 0.67 ± 0.61 (5) | 0.601 | 0.878 |