"click peptide"是指化学修饰后的多肽前体，它常常被用于研究多肽的生物学功能。我们在目的多肽的骨架上进行了化学修饰，构建多肽前体，且该前体不具备目的肽固有的生物学活性，当您收到多肽产品后，只需通过简单的操作如改变pH值，就能将前体肽原位转化为目的多肽，无副产物产生。该反应速度快，操作简单，且转化过程不可逆。

我们的click peptide服务参考了Atsuhiko Taniguchi等科学家研发的O-酰基肽方法（O-acyl isopeptide method，图一）。多肽链间的氢键作用力可维持高级结构的构象稳定，从而在物理化学性质及生物学功能中起着至关重要的作用。在pH值为7.4或更高的条件下，前体肽链中发生原子经济性反应（atom-economical reaction），通过O→N分子内酰基转移，迅速形成酰胺键。由于前体肽在转化过程中无副产品释放，因此在毒理学研究试验中将占很大的优势。

参考文献

Atsuhiko Taniguchi, Youhei Sohma, et al. Click peptide: Chemical Biology-oriented analogues of Alzheimer's amyloid β peptide 1–42. J. Peptide Science. Nov 2006; 12(12): 823-828

26-O-acyl β-amyloid (1-42) click peptide was successfully synthesized, the β-ester bond in which can be quickly and quantitatively converted to a native Gly25-Ser26 amide bond via a pH-dependent O-N intramolecular acyl migration reaction (t1/2 =1 min, pH 7.4, 37℃) at a hydroxyamino acid residue. Namely, upon this pH-triggered conversion (pH-click), the non-aggregative and water-soluble precursor (click peptide) can produce the monomer with a random-coil structure under physiological conditions (pH 7.4, 37℃). The structure information is as follows.

Scheme 2: β-amyloid (1-42) click peptide Result

Result

• β-amyloid precursor(click peptide) has a water solubility of 15 mg/ml, while it is only 0.14 mg/ml for the native peptide.
• The aggregative property of the peptides reduced significantly.
• The O-acyl moiety was stable under acidic pH.

Scheme 3: HPLC report of purified β-amyloid (1-42) native peptide converted from β-amyloid (1-42) click peptide (precursor)

Scheme 4: HPLC report of purified 26-O-acyl β-amyloid (1-42) click peptide (precursor)