Furthermore, oxidation of residue C358 inhibits PKM2 activity and promotes the metabolic changes required for proliferation (Anastasiou et al., 2011).
Being prone to oxidation, this residue readily undergoes selenoxide pyrolysis in the presence of H2O2 to yield dehydroalanine, a Michael acceptor.
Variable modifications were set to GlyGly modification of lysine residues, oxidation of methionine residues, and pyroglutamate formation of N-terminal glutamine residues.
Dynamic modifications consisted of DiLeu labels on lysine residues, oxidation of methionine residues (+15.99492 Da), deamidation of asparagine and glutamine residues (+0.98402 Da), and methylation of C termini and aspartic acid, glutamic acid, histidine, lysine, arginine, serine, and threonine residues (+14.01565 Da).
Acetylation of N-terminal residues; oxidation of methionine residues, Arg-6, Arg-10; and formation of pyroglutamic acid for peptides containing an N-terminal glutamine were considered as variable modifications.
The intrinsic fluorescence of FPs includes a unique chromophore that is formed post-translationally within the protein upon autocatalytic cyclization and oxidation of residues X-Tyr-Gly [ 46].
The GFP chromophore is comprised of a 4-hydroxybenzylidene imidazolinone structure formed from a self-catalyzed cyclization, dehydration, and oxidation of residues Ser65, Tyr66, and Gly67.
Oxidation of heavy residue: Heavy residue + O 2 → CO + CO 2 + H 2 O (3).
Possible modifications such as alkylation of cysteine residues and oxidation of methionine residues as well as other possible modifications (e.g. +203 Da on threonine and serine residues), were included in the search parameters.
Searches were performed allowing for complete carbamidomethylation (alkylation) of cysteine residues, partial oxidation of methionine residues, one missed cleavage and a mass error of 250 ppm.
