title: Synthesis of tetrapeptide Bz-RGDS-NH2 by a combination of chemical and enzymatic methods.
abstract: The tetrapeptide Bz-Arg-Gly-Asp-Ser-NH(2) (Bz-RGDS-NH(2)) was successfully synthesized by a combination of chemical and enzymatic methods in this study. Firstly, the precursor tripeptide Gly-Asp-Ser-NH(2) (GDS-NH(2)) was synthesized by a novel chemical method in four steps including chloroacetylation of l-aspartic acid, synthesis of chloroacetyl l-aspartic acid anhydride, the synthesis of ClCH(2)COAsp-SerOMe and ammonolysis of ClCH(2)COAsp-SerOMe. Secondly, lipase (PPL) was used to catalyze the formation of Bz-RGDS-NH(2) in aqueous water-miscible organic cosolvent systems using Bz-Arg-OEt as the acyl donor and GDS-NH(2) as the nucleophile. The optimum conditions were Bz-Arg-OEt 50 mM; GDS-NH(2) 400 mM; 10 degrees C, 0.1M phosphate buffer, pH 7.5; 60% DMF or 58% DMSO, PPL: 10 mg ml(-1) with the maximum yields of the tetrapeptide of 73.6% for DMF and 70.4% for DMSO, respectively. The secondary hydrolysis of the tetrapeptide product did not take place due to the absence of amidase activity of lipase.
authors.affiliation: Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, Jilin University, Changchun 130021, PR China.
authors.forename: Yi-Bing
authors.initials: YB
authors.lastname: Huang
authors.forename: Yu
authors.initials: Y
authors.lastname: Cai
authors.forename: Sen
authors.initials: S
authors.lastname: Yang
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.forename: Rui-Zhen
authors.initials: RZ
authors.lastname: Hou
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.forename: Wu
authors.initials: W
authors.lastname: Xiao-Xia
authors.forename: Xue-Zhong
authors.initials: XZ
authors.lastname: Zhang
mesh_terms: D002384:Catalysis; D015392:Chemistry, Inorganic / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D008049:Lipase / Q000494:pharmacology*; D009842:Oligopeptides / Q000138:chemical synthesis*; D009994:Osmolar Concentration; D012997:Solvents / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000494:pharmacology
chemical_list: D009842:Oligopeptides; D012997:Solvents; D014867:Water; C046617:arginyl-glycyl-aspartyl-serine; D008049:Lipase