EC Number   |
Substrates |
Organism  |
Products |
Reversibility |
|---|
   4.4.1.17 | Apocytochrome c + heme |
- |
Candida albicans |
Holocytochrome c |
- |
? |
| 4.4.1.17 | Apocytochrome c + heme |
reaction is catalyzed by a complex formed by two enzymes: CcmF and CcmH |
Escherichia coli |
Holocytochrome c |
- |
? |
| 4.4.1.17 | Apocytochrome c + heme |
- |
Homo sapiens |
Holocytochrome c |
- |
? |
| 4.4.1.17 | Apocytochrome c + heme |
conserved His154 is the key ligand to the heme iron, formation of the enzyme-heme complex serves as the platform for interaction with apocytochrome c, the heme is the central molecule mediating contact between enzyme and apocytochrome c. Conserved His19 of the CXXCH motif in apocytochrome c supplies the second axial ligand to heme in the trapped enzyme-heme-cytochrome c complex. Molecular mechanisms, overview |
Homo sapiens |
Holocytochrome c |
- |
? |
| 4.4.1.17 | Apocytochrome c + heme |
the catalytic function of the enzyme depends on its ability to coordinate interactions between its substrates: heme and cytochrome c, four-step model describing enzyme-mediated cytochrome c assembly, identifying conserved histidine residue 154 as an axial ligand to the heme iron, overview. The enzyme contains two heme-binding domains, heme contacts mediated by residues within these domains modulate the dynamics of heme binding and contribute to the stability of the enzyme-heme-cytochrome c steady state ternary complex. While some residues are essential for initial heme binding, others impact the subsequent release of the holocytochrome c product |
Homo sapiens |
Holocytochrome c |
- |
? |
| 4.4.1.17 | Apocytochrome c + heme |
the enzyme attaches heme to wild-type cytochrome, and to mutant cytochromes containing individual cysteine, histidine, and double cysteine of conserved motif CXXCH, but not the mutant with triple cysteine/histidine substitutions, overview. His19 in cytochrome c is important for 1. to provide the second axial ligand to the heme iron in preparation for covalent attachment, 2. to spatially position the two cysteinyl sulfurs adjacent to the two heme vinyl groups for thioether formation, and 3. to aid in release of the holocytochrome c from the enzyme's active site. Substitutions of His19 in cytochrome c to seven other residues (G,A,M,R,K,C,Y) show that only mutant H19M is able to carry out these three roles, albeit at lower efficiencies than the wild-type His19. The histidine in the CXXCH motif acts as an axial ligand to the heme iron |
Homo sapiens |
Holocytochrome c |
- |
? |
| 4.4.1.17 | apocytochrome c1 + heme |
- |
Homo sapiens |
holocytochrome c1 |
- |
? |
| 4.4.1.17 | more |
substrate specificity of the human enzyme, overview. Engineering of a bacterial cytochrome c into a robust substrate for the human enzyme, overview |
Homo sapiens |
? |
- |
? |
| 4.4.1.17 | more |
HCCS mediates heme attachment to the N-terminal cysteine in cytochrome c C-terminal variants, but up to 50% of the cytochrome c produced is modified in an oxygen-dependent manner, resulting in a mixed population of cytochrome c. Natural HCCS-mediated heme attachment to C-terminal cytochrome variants likely initiates at the C-terminal cysteine |
Homo sapiens |
? |
- |
? |
| 4.4.1.17 | Apocytochrome c + heme |
- |
Mus musculus |
Holocytochrome c |
- |
? |
