TABLE III.
Comparison of Apparent Rate and Equilibrium Constants for Hemin Binding to apoShp, apoHtsA, and other hemin protein complexes
| Heme protein |
k′hemin μM−1 s−1 |
k-hemin s−1 |
Khemin nM−1 |
Reference |
|---|---|---|---|---|
| Sperm Whale apoMb | ~70 | 0.000001 | ~70,000 | 30 |
| H93G SW apoMb | ~70 | 0.012 | ~5 | 30 |
| BSA (hemin) | ~50 | 0.011 | ~4 | 30 |
| Hemophore HasA | 53 | 29 | ||
| ApoShp | This work | |||
| without apoHtsA | 1.6 | 0.0003 | 5 | |
| with apoHtsA | 43 | |||
| ApoHtsA | 80 | 0.0026 | 31 | This work |
| Human apohemoglobin | 31 | |||
| α (tetramers) | ~100 | 0.00008 | ~1200 | |
| α (dimers) | ~100 | 0.00016 | ~600 | |
| α (monomers) | ~100 | 0.0033 | ~33 | |
| β (tetramers) | ~100 | 0.00041 | ~250 | |
| β (dimers) | ~100 | 0.0042 | ~24 | |
| β (monomers) | ~100 | 0.011 | ~9 |