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) | 8 | |
| CYS | None | Heme/heme-like | Amino-acid side chain (Any position) | 3724 | |
| CYS | None | Heme/heme-like | Amino-acid side chain (Any position) | 3387 | |
| CYS | None | Heme/heme-like | Amino-acid side chain (Any position) | 2 | |
| LYS | None | Heme/heme-like | Amino-acid side chain (Any position) | 32 | |
| TYR | None | Heme/heme-like | Amino-acid side chain (Any position) | 33 | |
| TYR | None | Heme/heme-like | Amino-acid side chain (Any position) | 24 | |
| TYR | None | Heme/heme-like | Amino-acid side chain (Any position) | 9 | |
| LYS | None | Heme/heme-like | Amino-acid side chain (Any position) | 4 | |
| CYS | None | Heme/heme-like | Amino-acid side chain (Any position) | 1 | |
| CYS | None | Heme/heme-like | Amino-acid side chain (Any position) | 0 |
