Table 3.
Amino acids in collagen with their corresponding post-translation modification, added group and enzyme involved. The outcome of overexpression of each modification is described in the last column
| Amino acids | PTM | Group | Enzymes | Outcome if increased |
|---|---|---|---|---|
| Proline | Hydroxylation (ER) | –OH | P4Hs, P3Hs | Hypoxia |
| Lysine | Hydroxylation (ER) | –OH | LH1, LH2, LH3 | Increased glycosylation, crosslinking and fibrosis |
| Hydroxylysine |
N-Linked (ER) O-linked (GA) Glycosylation |
Glucose or galactose |
COLGALT1, COLGALT2, GT, GGT |
Increased crosslinking, matrix stiffness |
| Lysine/Hydroxylysine | Oxidation (ES) | –O | LOX, LOXL1, LOXL2, LOXL3, LOXL4 | Fibrosis, matrix stiffness |
| Arginine | Citrullination (ES) |
Citrulline H2O to NH4 + |
PAD4 |
Role in protein folding, apoptosis, TGF-β Pathway, receptor binding |