Multiple post-translational modification sites have been observed, yet there are still many unanswered questions regarding the precise roles of these modifications in controlling the contradicting functions of E2F1.
Proteomics research has shown that several subunits of the enzymes in the mitochondrial ETC and TCA cycle have multiple acetylation modification sites, and increased acetylation was observed in Sirt3−/− tissues, indicating that the enzyme activities may be regulated by Sirt3.
However, irrespective of the origin of the reducing sugars and proteins, the common molecular structures observed at the modification sites of AGE are Nɛ- carboxy methyl- l-lysiNɛ- carboxy methyl-ne, imidazolone and pyrraline.
We suspect that the equivalent relative reactivity of Cys-113 and His-157 observed in mapping the amino acid modification sites is due to a stepwise saturation of Cys-113, followed by modification of His-157, resulting from the large amount of HNE used (2 mM) in this experiment.
Finally, we observed that Met-44, one of the major modification sites, has an important role in the activation of procaspase-3.
It is clear that many commonly observed co-operative motif pairings reflect the available motif-binding pockets in the binding partner, for example, docking motifs and modification sites for the same PTM enzyme will often occur in the same protein, increasing the efficiency and specificity of modification [ 78, 80, 103– 103].
Fig. 1 Modification sites based on compound 1.
Site annotations list any structurally/functionally important sites (molecule processing sites, binding sites, modification sites, etc).
Post-translational modification sites could provide another layer of complexity.
These changes at identical positions were designated "homologous modification sites".
