Lahm H W, Stein S
J Chromatogr. 1985 Jun 19;326:357-61. doi: 10.1016/s0021-9673(01)87461-6.
Highly purified recombinant human interleukin-2, expressed in Escherichia coli, was analyzed by micromethods. N-Terminal sequence analysis showed that methionine at position 0 was found in 90% of the molecules and not completely removed in post-ribosomal processing. A complete peptide map of the reduced and S-carboxymethylated protein was obtained by high-performance liquid chromatography after tryptic digestion, and the fragments were identified by amino acid analysis and automated Edman sequence analysis. Using a double-label S-carboxymethylation procedure, it was determined that there is a disulfide linkage between the cysteine residues at positions 58 and 105. The third cysteine residue at position 125 was found to be present as the free sulfhydryl.
对在大肠杆菌中表达的高度纯化的重组人白细胞介素-2 进行了微量方法分析。N 端序列分析表明，90% 的分子在第 0 位存在甲硫氨酸，且在核糖体后加工过程中未被完全去除。经胰蛋白酶消化后，通过高效液相色谱法获得了还原型和 S-羧甲基化蛋白的完整肽图，并通过氨基酸分析和自动 Edman 序列分析对片段进行了鉴定。采用双标记 S-羧甲基化方法，确定在第 58 位和第 105 位的半胱氨酸残基之间存在二硫键。发现第 125 位的第三个半胱氨酸残基以游离巯基形式存在。
