1. Synthesis of a precursor tripeptide Z-Asp-Val-Tyr-OH of thymopentin by chemo-enzymatic method
Kun Zheng, Ruiyan Zhan, Yang Hong, Jing Li, Wei Shi, Shijun Li Prep Biochem Biotechnol. 2012;42(6):520-34. doi: 10.1080/10826068.2012.660902.
The precursor tripeptide of thymopentin was synthesized by a combination of chemical and enzymatic methods. First, Val-Tyr-OH dipeptide was synthesized by a novel chemical method in two steps involving preparation of NCA-Val. Second, the linkage of the third amino acid Z-Asp-OMe to Val-Tyr-OH was completed by an enzymatic method under kinetic control. An industrial alkaline protease alcalase was used in water-organic cosolvent systems. The synthesis reaction conditions were optimized by examining the effects of several factors including organic solvents, water content, temperature, pH, and reaction time on the yield of Z-Asp-Val-Tyr-OH. The optimum condition is of pH 10.0, 35°C, acetonitrile/Na₂CO₃-NaHCO₃ buffer system (85:15, v/v), and reaction time of 2.5 hr, which achieves tripeptide yield of more than 70%.
2. Visible-Light Microscopic Discovery of Up to 150 μm Long Helical Amyloid Fibrils Built of the Dodecapeptide H-(Val-Ala-Leu)4 -OH and of Decapeptides Derived from Insulin
Monika Świontek, Zbigniew J Kamiński, Beata Kolesińska, Dieter Seebach Chem Biodivers. 2016 Sep;13(9):1111-1117. doi: 10.1002/cbdv.201600167. Epub 2016 Aug 31.
In the formation of amyloid fibrils from small peptides, the appearance of superhelices of (P)- or (M)-helicity has been observed for the first time; high concentrations of the peptides and extended periods of incubation at physiological pH appear to be important for this phenomenon. In view of the general importance of peptide and protein aggregation, we give a brief overview with selected examples for demonstration.
