Chiari M, Ettori C, Righetti P G, Colonna S, Gaggero N, Negri A
Departement of Biomedical Sciences and Technologies, University of Milano, Italy.
Electrophoresis. 1991 May;12(5):376-7. doi: 10.1002/elps.1150120510.
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.
聚丙烯酰胺凝胶中过硫酸盐的存在是否会导致蛋白质中的半胱氨酸（Cys）氧化为半胱磺酸，这一问题一直存在争议。事实上，将牛血清白蛋白（BSA）与过二硫酸盐和高碘酸盐直接孵育，几乎不会改变其等电点（pI），也不会产生任何半胱磺酸。相比之下，过氧单硫酸盐和过邻苯二甲酸盐会显著降低BSA的pI。在前一种情况下，已证明（总共35个中的）4个半胱氨酸被转化为半胱磺酸。到目前为止，发现过邻苯二甲酸盐是最强的氧化剂：（35个中的）15个半胱氨酸残基被氧化为半胱磺酸，所有甲硫氨酸基团均被破坏。
