Table 1.
Relative Mitochondrial Enzyme Activities for NFU1, BOLA3, and ISCU Mutant Fibroblasts
| Enzyme | [Fe-S] Clusters | NFU1 Mutant Individuals6 | BOLA3 Mutant Individual6 | ISCU Mutant Individuals13–15 |
|---|---|---|---|---|
| Complex I (I+III) | [2Fe-2S] (×2), [4Fe-4S] (×6) | ∼30% | ∼30% | ∼70% |
| Complex II | [2Fe-2S], [3Fe-4S], [4Fe-4S] | 50% | 50% | ∼20% |
| Complex III | [2Fe-2S] | ∼60% | ∼60% | ∼40% |
| Complex IV | ∼50% in 2 sibs, normal in 1 sib | normal | normal | |
| Mitochondrial Aconitase | [4Fe-4S] | normal | normal | ∼30% |
| PDHc | requires covalently attached lipoate on E2 | ∼5−10% | ∼5−10% | ND |
| E2 | requires covalently attached lipoate on E2, but assay works with added lipoic acid | normal | ND | ND |
| E3 | normal | ND | ND | |
| OGDHc | lipoate requiring | ∼10% | ∼30% | ND |
ND is used as an abbreviation for not determined.