| GO:0005506 | iron ion binding | 15 |
| GO:0031418 | L-ascorbic acid binding | 15 |
| GO:0016702 | oxidoreductase activity, acting on single donors with incorporation of molecular oxygen, incorporation of two atoms of oxygen | 14 |
| GO:0004656 | procollagen-proline 4-dioxygenase activity | 14 |
| GO:0005783 | endoplasmic reticulum | 14 |
| GO:0016706 | oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, 2-oxoglutarate as one donor, and incorporation of one atom each of oxygen into both donors | 3 |
| GO:0016705 | oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen | 2 |
| GO:0008270 | zinc ion binding | 1 |
| GO:0005634 | nucleus | 1 |
