Aim To synthesize thymosin α _1 by the solid-phase method.Methods Peptide
synthesis was performed manually by the stepwise
solid-phase method using the base-labile Fmoc group for protecting the α -amino acid.The peptide was assembled on a p -alkoxybenzyl alcohol resin.And the peptide sequence was prepared employing Fmoc-amino acid and Boc-
protected Lys,O t Bu-protected Asp,Glu,t Bu-protected Ser,Thr,Trt-protected Asn as building blocks.The Fmoc group was removed with piperidine-DCM( V∶V =1∶1).The peptide resin was treated with TFA-DCM( V∶V =1∶1),and purified by ion-exchange chromatography and prepared RP-HPLC.The analytical strategies included the reaction of ninhydrin reagents with small samples of resin peptide and salicylaldehyde reagents testing methods were used to monitor solid-phase reactions and determine the structures of resin-bound compounds.Results The yield of the total
synthesis was 33.2%,based on the amino acid content of the starting Fmoc-Asn(Trt)-resin.The purity was range to above 98.8%,the activity is equal to that of Zadaxin.Conclusion A strategy for the synthesis of thymosin α _1 was presented.This orthogonal protection strategy has bright prospects for peptide synthesis.