title: Synthesis of a precursor tripeptide Z-Asp-Val-Tyr-OH of thymopentin by chemo-enzymatic method.
abstract: 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%.
authors.affiliation: Key Laboratory for Molecular Enzymology and Engineering, Ministry of Education, Jilin University, Changchun, P.R. China.
authors.forename: Kun
authors.initials: K
authors.lastname: Zheng
authors.forename: Ruiyan
authors.initials: R
authors.lastname: Zhan
authors.forename: Yang
authors.initials: Y
authors.lastname: Hong
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Shi
authors.forename: Shijun
authors.initials: S
authors.lastname: Li
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000596:Amino Acids / Q000737:chemistry; D002021:Buffers; D060326:Chemistry Techniques, Synthetic / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D004789:Enzyme Activation; D006863:Hydrogen-Ion Concentration; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification; D017693:Sodium Bicarbonate / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013381:Subtilisins / Q000737:chemistry; D013696:Temperature; D016305:Thymopentin / Q000737:chemistry*; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D000596:Amino Acids; D002021:Buffers; D009842:Oligopeptides; D012997:Solvents; D014867:Water; D017693:Sodium Bicarbonate; D013381:Subtilisins; D016305:Thymopentin; C032159:acetonitrile