Bernatowicz M S, Matsueda R, Matsueda G R
Int J Pept Protein Res. 1986 Aug;28(2):107-12. doi: 10.1111/j.1399-3011.1986.tb03236.x.
The 3-nitro-2-pyridinesulfenyl (Npys) derivative of cysteine was prepared and used to facilitate the formation of an unsymmetrical disulfide bond. Since this derivative is stable in trifluoroacetic acid:CH2 Cl2 (1:1) and anhydrous hydrogen fluoride, Boc-Cys(Npys) could be used directly in solid phase synthesis of the 14-peptide acetyl-Cys(Npys)-Gly-Glu-Gln-Gln-His-His-Pro-Gly-Gly-Gly-Ala-Lys-G ln-Ala-amide. Reaction of this peptide with the free thiol of another peptide, acetyl-Gly-Glu-Gln-His-His-Pro-Gly-Gly-Gly-Ala-Lys-Gln-Cys-amide, gave a single product containing an unsymmetrical disulfide bond. The amino acid composition of this product and HPLC analysis of its dithiothreitol reduction products were consistent with the desired heterodimer. As evidenced by HPLC, the mixed disulfide forms rapidly at alkaline pH and usefully over a wide pH range in aqueous buffers.
制备了半胱氨酸的3-硝基-2-吡啶亚磺酰基（Npys）衍生物，并用于促进不对称二硫键的形成。由于该衍生物在三氟乙酸：二氯甲烷（1:1）和无水氟化氢中稳定，Boc-Cys（Npys）可直接用于14肽乙酰基-Cys（Npys）-Gly-Glu-Gln-Gln-His-His-Pro-Gly-Gly-Gly-Ala-Lys-Gln-Ala-酰胺的固相合成。该肽与另一种肽乙酰基-Gly-Glu-Gln-His-His-Pro-Gly-Gly-Gly-Ala-Lys-Gln-Cys-酰胺的游离硫醇反应，得到了一种含有不对称二硫键的单一产物。该产物的氨基酸组成及其二硫苏糖醇还原产物的HPLC分析与所需的异二聚体一致。如HPLC所示，混合二硫键在碱性pH下迅速形成，并且在水性缓冲液的宽pH范围内有效形成。
