title: Synthesis of a precursor dipeptide of thymopentin in organic solvents by an enzymatic method.
abstract: The protease-catalyzed, kinetically controlled synthesis of a precursor dipeptide of thymopentin(TP-5), Z-Arg-Lys-NH2 in organic solvents was studied. Z-Arg-OMe was used as the acyl donor and Lys-NH2 was used as the nucleophile. An industrial alkaline protease alcalase and trypsin were 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-Arg-Lys-NH2. The optimum conditions using alcalase as the catalyst are pH 10.0, 35 degrees C, in acetonitrile/DMF/Na2CO3-NaHCO3 buffer system (80:10:10, V/V), 6 h, with the dipeptide yield of 71.1%. Compared with alcalase, the optimum conditions for trypsin are pH 8.0, 35 degrees C, in ethanol/Tris-HCl buffer system (80:20, V/V), 4 h, with the dipeptide yield of 76.1%.
authors.affiliation: Key Laboratory for Molecular Enzymology and Engineering, Ministry of Education, Jilin University, Changchun, PR China.
authors.forename: Shi-Jun
authors.initials: SJ
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhao
authors.forename: Yi-Bing
authors.initials: YB
authors.lastname: Huang
authors.forename: Gui
authors.initials: G
authors.lastname: Gao
authors.forename: Dai-Hui
authors.initials: DH
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.forename: Gang
authors.initials: G
authors.lastname: Li
authors.forename: Xue-Zhong
authors.initials: XZ
authors.lastname: Zhang
mesh_terms: D000581:Amidohydrolases / Q000737:chemistry*; D004151:Dipeptides / Q000138:chemical synthesis*; D009930:Organic Chemicals / Q000737:chemistry*; D011498:Protein Precursors / Q000138:chemical synthesis*; D012997:Solvents / Q000737:chemistry*; D016305:Thymopentin / Q000737:chemistry*; D014357:Trypsin / Q000737:chemistry*
chemical_list: D004151:Dipeptides; D009930:Organic Chemicals; D011498:Protein Precursors; D012997:Solvents; D014357:Trypsin; D000581:Amidohydrolases; C019665:amidase; D016305:Thymopentin