Stüber W, Hemmasi B, Bayer E
Int J Pept Protein Res. 1983 Sep;22(3):277-83. doi: 10.1111/j.1399-3011.1983.tb02094.x.
The synthesis of the C-terminal nonapeptide of bovine insulin B-chain is described. 4-(Bromomethyl)-3-nitrobenzoylglycyl-poly(ethylene glycol) Mr = 15,000) was used as soluble support. The C-terminal alanine was first converted to Boc-Ala-O-(2-nitro-4-carboxy) benzyl ester which was then coupled to Gly-PEG via DCC activation. The synthesis was performed using the in situ symmetrical anhydride coupling method. Cleavage of the protected peptide from the polymeric support was achieved by photolysis. The product was then chromatographed on a column of Sephadex LH-20. All the protecting groups of a sample were removed with liquid HF and the unprotected crude peptide was purified by ion-exchange chromatography on CM-Sephadex to obtain an electrophoretically and chromatographically pure peptide. The identity of this peptide was confirmed by field desorption mass spectrometry and amino acid analysis. Circular dichroism measurement suggests that the free nonapeptide possesses a disordered conformation. The nonapeptide was tested for the racemization of the individual amino acids by gas chromatography and the results showed that no residue was significantly racemized.
本文描述了牛胰岛素B链C端九肽的合成。使用4-(溴甲基)-3-硝基苯甲酰甘氨酰-聚乙二醇（分子量15,000）作为可溶性载体。首先将C端丙氨酸转化为Boc-Ala-O-(2-硝基-4-羧基)苄酯，然后通过二环己基碳二亚胺（DCC）活化将其与甘氨酰-聚乙二醇偶联。合成采用原位对称酸酐偶联法进行。通过光解从聚合物载体上裂解保护肽。然后将产物在Sephadex LH-20柱上进行色谱分离。用液体HF除去样品的所有保护基团，未保护的粗肽通过在CM-Sephadex上进行离子交换色谱纯化，以获得电泳和色谱纯的肽。通过场解吸质谱和氨基酸分析确认了该肽的身份。圆二色性测量表明游离九肽具有无序构象。通过气相色谱法测试了该九肽中各个氨基酸的消旋化情况，结果表明没有残基发生明显消旋。
