Oxidation of cysteine to cysteic acid in proteins by peroxyacids, as monitored by immobilized pH gradients.
It has often been debated whether the presence of persulfate in a polyacrylamide gel could lead to the oxidation of cysteine (Cys) in proteins to cysteic acid. In fact, direct incubation of bovine serum albumin (BSA) with peroxodisulfate and periodate barely alters the isoelectric point (pI) and does not produce any cysteic acid. In contrast, caroate (peroxomonosulfate) and perphthalate strongly lower the pI of BSA. In the former case it as demonstrated that 4-Cys (of a total of 35) were converted into cysteic acid. Perphthalate was found to be, by far, the strongest oxidant: 15 (of 35) Cys residues were oxidized to cysteic acid and all methionine groups were destroyed.
Chiari
M
M
Departement of Biomedical Sciences and Technologies, University of Milano, Italy.
Ettori
C
C
Righetti
P G
PG
Colonna
S
S
Gaggero
N
N
Negri
A
A
D000645:Ammonium Sulfate / Q000494:pharmacology*; D003544:Cysteic Acid; D003545:Cysteine / Q000187:drug effects*; D004852:Epoxy Compounds / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D008715:Methionine; D010084:Oxidation-Reduction; D010504:Periodic Acid / Q000494:pharmacology*; D010795:Phthalic Acids / Q000494:pharmacology*; D011506:Proteins / Q000187:drug effects*; D012710:Serum Albumin, Bovine / Q000187:drug effects; D013464:Sulfuric Acids / Q000494:pharmacology*
D004852:Epoxy Compounds; D010795:Phthalic Acids; D011506:Proteins; D013464:Sulfuric Acids; D010504:Periodic Acid; C061799:dioxirane; C031276:ammonium peroxydisulfate; C037624:monoperphthalic acid; D012710:Serum Albumin, Bovine; D003544:Cysteic Acid; D008715:Methionine; C009288:metaperiodate; C048813:potassium peroxymonosulfuric acid; D003545:Cysteine; D000645:Ammonium Sulfate