title: Trypsin-catalyzed kinetically controlled synthesis of a precursor dipeptide of thymopentin in organic solvents, using a free amino acid as nucleophile.
abstract: Trypsin-catalyzed, kinetically controlled synthesis of a precursor, dipeptide of thymopentin (TP-5), Bz-Arg-Lys-OH (or-OEt) in organic solvents was studied. Bz-Arg-OEt was used as the acyl donor and Lys-OH and Lys-OEt were used as the nucleophiles. Ethanol was selected as the organic solvent from ethanol, methanol, acetonitrile, and ethyl acetate tested under the experimental conditions. As expected, Lys-OEt is not a suitable nucleophile in trypsin-catalyzed reaction, due to its competition with the protective Arg-OEt as acyl donor for the active site of trypsin, while Lys-OH does not have this problem. The optimal reaction condition for the synthesis of Bz-Arg-Lys-OH was set up as 20% Tris-HCl buffer, pH 8.0, 35 degrees C for 6 h with the yield of 52.5%, or for 18-24 h with the yield of about 60%.
authors.affiliation: Key Laboratory of Molecular Enzymology and Engineering, Jilin University, Changchun, PR China.
authors.forename: Na
authors.initials: N
authors.lastname: Wang
authors.forename: Yi-Bing
authors.initials: YB
authors.lastname: Huang
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.forename: Xiao-Xia
authors.initials: XX
authors.lastname: Wu
authors.forename: Xue-Zhong
authors.initials: XZ
authors.lastname: Zhang
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D004151:Dipeptides / Q000138:chemical synthesis*; D011498:Protein Precursors / Q000138:chemical synthesis; D012997:Solvents; D016305:Thymopentin / Q000138:chemical synthesis*; D014357:Trypsin / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D004151:Dipeptides; D011498:Protein Precursors; D012997:Solvents; D014357:Trypsin; D016305:Thymopentin