Cadée J A, van Steenbergen M J, Versluis C, Heck A J, Underberg W J, den Otter W, Jiskoot W, Hennink W E
Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, The Netherlands.
Pharm Res. 2001 Oct;18(10):1461-7. doi: 10.1023/a:1012213108319.
The oxidation of recombinant human interleukin-2 (rhlL-2) by potassium peroxodisulfate (KPS) with or without N,N,N',N'-tetramethylethylenediamine (TEMED), which are used for the preparation of dextran-based hydrogels, was investigated.
The oxidation of (derivatives of) methionine. tryptophan, histidine and tyrosine, as well as rhlL-2 was investigated. Both the oxidation kinetics (RP-HPLC) and the nature of the oxidation products (mass spectrometry) were studied as a function of the KPS and TEMED concentration, and the presence of a competitive antioxidant, methionine.
Under conditions relevant for the preparation of rhIL-2 loaded hydrogels, only methionine and tryptophan derivatives were susceptible to oxidation by KPS. The oxidation of these compounds was inhibited once TEMED was present, suggesting that the peroxodisulfate anion, rather than the radicals formed in the presence of TEMED, is the oxidative species. KPS only induced oxidation of the four methionines present in rhIL-2, whereas the tryptophan residue remained unaffected. The radicals, formed after KPS decomposition by TEMED, induced some dimerization of rhIL-2. The oxidation of rhIL-2 could be substantially reduced by the addition of methionine, or by pre-incubation of KPS with TEMED.
Only the methionine residues in rhlL-2 are oxidized by KPS. The extent of oxidation can be minimized by a proper selection of the reaction conditions.
研究过二硫酸钾（KPS）在有或没有N，N，N'，N'-四甲基乙二胺（TEMED）存在的情况下对重组人白细胞介素-2（rhlL-2）的氧化作用，这两种物质用于制备基于葡聚糖的水凝胶。
研究了甲硫氨酸、色氨酸、组氨酸和酪氨酸（及其衍生物）以及rhlL-2的氧化情况。研究了氧化动力学（反相高效液相色谱法）和氧化产物的性质（质谱法）与KPS和TEMED浓度以及竞争性抗氧化剂甲硫氨酸存在与否的关系。
在与制备负载rhIL-2的水凝胶相关的条件下，只有甲硫氨酸和色氨酸衍生物易被KPS氧化。一旦存在TEMED，这些化合物的氧化就会受到抑制，这表明过二硫酸根阴离子而非TEMED存在时形成的自由基是氧化物种。KPS仅诱导rhIL-2中存在的四个甲硫氨酸氧化，而色氨酸残基未受影响。TEMED使KPS分解后形成的自由基诱导了rhIL-2的一些二聚化。添加甲硫氨酸或KPS与TEMED预孵育可大幅降低rhIL-2的氧化。
KPS仅氧化rhlL-2中的甲硫氨酸残基。通过适当选择反应条件可将氧化程度降至最低。
