HEC
PCM
| Residue type | PCM type | Category | Position | UniProt PTM accession | Entries in PDB |
| ASP | None | Heme/heme-like | Amino-acid side chain (Any position) | 0 | |
| CYS | None | Heme/heme-like | Amino-acid side chain (Any position) | 3843 | |
| CYS | None | Heme/heme-like | Amino-acid side chain (Any position) | 3226 | |
| CYS | None | Heme/heme-like | Amino-acid side chain (Any position) | 53 | |
| CYS | None | Heme/heme-like | Amino-acid side chain (Any position) | 25 | |
| CYS | None | Heme/heme-like | Amino-acid side chain (Any position) | 4 | |
| LYS | None | Heme/heme-like | Amino-acid side chain (Any position) | 4 | |
| LYS | None | Heme/heme-like | Amino-acid side chain (Any position) | 27 | |
| TYR | None | Heme/heme-like | Amino-acid side chain (Any position) | 37 | |
| TYR | None | Heme/heme-like | Amino-acid side chain (Any position) | 24 | |
| TYR | None | Heme/heme-like | Amino-acid side chain (Any position) | 12 | |
| ASN | None | Metal coordination | Amino-acid side chain (Any position) | 3 | |
| ASP | None | Metal coordination | Amino-acid side chain (Any position) | 0 | |
| CSS | None | Metal coordination | Amino-acid side chain (Any position) | 23 | |
| CSS | None | Metal coordination | Amino-acid side chain (Any position) | 3 | |
| CYS | None | Metal coordination | Amino-acid side chain (Any position) | 67 | |
| GLU | None | Metal coordination | Amino-acid side chain (Any position) | 2 | |
| GLY | None | Metal coordination | Amino-acid backbone (Any position) | 2 | |
| HIS | None | Metal coordination | Amino-acid side chain (Any position) | 6410 | |
| HIS | None | Metal coordination | Amino-acid side chain (Any position) | 5 | |
| LYS | None | Metal coordination | Amino-acid side chain (Any position) | 124 | |
| MET | None | Metal coordination | Amino-acid side chain (Any position) | 1354 | |
| SER | None | Metal coordination | Amino-acid side chain (Any position) | 2 | |
| THR | None | Metal coordination | Amino-acid backbone (Any position) | 1 | |
| TYR | None | Metal coordination | Amino-acid side chain (Any position) | 59 | |
| TYR | None | Metal coordination | Amino-acid backbone (Any position) | 46 |
