1.Synthesis of a precursor tripeptide Z-Asp-Val-Tyr-OH of thymopentin by chemo-enzymatic method.
Zheng K1, Zhan R, Hong Y, Li J, Shi W, Li S. 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.Protease-catalyzed synthesis of a precursor dipeptide, Z-Asp-Val-NH2 of thymopentin, in organic solvents.
Li SJ1, Wang JA, Xu L, Zhang XZ, Li J, Suo D. Prep Biochem Biotechnol. 2008;38(4):334-47. doi: 10.1080/10826060802325402.
The protease-catalyzed, kinetically controlled synthesis of a precursor dipeptide, Z-Asp-Val-NH(2) of thymopentin (TP-5), in organic solvents was studied. Z-Asp-OMe and Val-NH(2) were used as the acyl donor and the nucleophile, respectively. An industrial alkaline protease alcalase was used to catalyze the synthesis of the target dipeptide in water-organic cosolvent systems. The conditions of the synthesis reaction 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-NH(2). The optimum conditions using alcalase as the catalyst are pH 10.0, 35 degrees C, in acetonitrile/Na(2)CO(3)-NaHCO(3) buffer system (9:1, V/V), reaction time 5 h, with a yield of 63%. The dipeptide product was confirmed by LC- MS.
