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
From: Understanding the matrix: collagen modifications in tumors and their implications for immunotherapy
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 |