Chemical Synthesis, Separation And Purification Of Thymosin α₁ And Anti-SARS Octapeptide

In this thesis, the effects of different coupling reagents on chemical synthesis ofthymosin α1 were studied systemically. The optimal synthetic technology wasobtained: the coupling reagent was HBTU with 2-4 equiv. amino acid at a couplingrate of 11 h per amino acid. The yields of crude thymosin α1 was 89.9% with a purityof 31.2%, and the cost was 2.49 RMB per mg of thymosin α1. By using ion-exchangechromatography (IEC) and reversed-phase high performance liquid chromatography(RP-HPLC), thymosin α1 was isolated and purified from the crude productsynthesized. The purity of the final product attained to 95% through IEC on DEAESepharose Fast Flow and RP-HPLC on Delta-PakTM C18 respectively after optimizingthe chromatographic conditions. The capacity of purification process was arrived 50mg per circle. The total recovery was 36%. The technology is simple and reliable, andcan be scaled up easily. Additional, the chemical synthesis of anti-SARS octapeptide screening by K. C.Chou er al. was also studied. The optimal synthetic technology was obtained: thecoupling reagent was HBTU with 2 equiv. amino acid at a coupling rate of 5 h peramino acid. The yields of crude octapeptide was 87.6% with a purity of 72.8%, andthe cost was 1.23RMB per mg of octapeptide. Then the crude product of octapeptidewas isolated and purified with RP-HPLC. The purity of the final product attained to95% after purification on Delta-PakTM C18. The recoveryd was 65%, and the capacityof purification process was arrived 10mg per circle. The results of bioactivityidentification indicated that octapeptide was the most active in inhibiting replicationof the SARS-associated virus, which showed that octapeptide was a potentialanti-SARS drug under development.