Table 1.
Heme Protein Database statistics
| Proteins and domains | |
| Number of heme proteins in PDB | 1414 |
| Number of hemes in PDB | 3013 |
| Number of heme proteins in HPD | 268 |
| Number of hemes in HPD | 738 |
| Number of heme proteins in CATH | 241 |
| Number of hemes in CATH domains | 638 |
| Reduction potentials | |
| Number of reduction potentials | 153 |
| Most negative reduction potential | −550 mV |
| Most positive reduction potential | 450 mV |
| Dissociation constants | |
| Number of dissociation constants | 10 |
| Weakest dissociation constant | 2.5 μM |
| Tightest dissociation constant | 300 pM |
| Heme type abundance | |
| Heme a | 13.6% |
| Heme b | 53.5% |
| Heme c | 40.9% |
| Heme d1 | 1.9% |