Institute for Molecular Bioscience, The University of Queensland, St Lucia, 4072, Australia.
J Pept Sci. 2012 Mar;18(3):199-207. doi: 10.1002/psc.1438. Epub 2012 Jan 17.
Benzotriazole-based coupling reagents have dominated the last two decades of solid phase peptide synthesis. However, a growing interest in synthesizing complex peptides has stimulated the search for more efficient and low-cost coupling reagents, such as COMU which has been introduced as a nonexplosive alternative to the classic benzotriazole coupling reagents. Here, we present a comparative study of the coupling efficiency of COMU with the benzotriazole-based HBTU and HCTU for use in in situ neutralization Boc-SPPS. Difficult sequences, such as ACP(65-74), Jung-Redeman 10-mer, and HIV-1 PR(81-99), were used as model target peptides on polystyrene-based resins, as well as polyethylene glycol-based resins. Coupling yields obtained using fast in situ Boc-SPPS cycles were determined with the quantitative ninhydrin test as well as via LC-MS analysis of the crude cleavage products. Our results demonstrate that COMU coupling efficiency was less effective compared to HBTU and HCTU with HCTU ≥ HBTU > COMU, when polystyrene-based resins were employed. However, when the PEG resin was employed in combination with a safety catch amide (SCAL) linker, more comparable yields were observed for the three coupling reagents with the same ranking HCTU ≥ HBTU > COMU.
苯并三唑基偶联试剂主导了过去二十年的固相肽合成。然而，对合成复杂肽的兴趣日益浓厚，刺激了人们寻找更有效、低成本的偶联试剂，如 COMU，它已被引入作为经典苯并三唑偶联试剂的无爆炸替代品。在这里，我们比较了 COMU 与基于苯并三唑的 HBTU 和 HCTU 在原位中和 Boc-SPPS 中的偶联效率。使用聚苯乙烯基树脂和聚乙二醇基树脂作为模型目标肽，对困难序列（如 ACP(65-74)、Jung-Redeman 10 肽和 HIV-1 PR(81-99)）进行了研究。使用快速原位 Boc-SPPS 循环获得的偶联产率通过定量茚三酮试验以及通过粗裂解产物的 LC-MS 分析来确定。我们的结果表明，与 HBTU 和 HCTU 相比，当使用聚苯乙烯基树脂时，COMU 的偶联效率较低，HCTU ≥ HBTU > COMU。然而，当使用聚乙二醇树脂并结合安全捕获酰胺（SCAL）接头时，对于三种偶联试剂观察到更可比的产率，相同的排序为 HCTU ≥ HBTU > COMU。
