摘要
本文用手动逐步法,以Boc-Ala-OCH_2-Pam树脂为载体,Boc保护的α-氨基酸为原料合成了十一个hTGF-α(人体转化生长因子-α)类似物。经过HF裂解、透析、二硫键配对合环及HPLC纯化,得到平均收率为2.9％的纯品,其氨基酸组成分析及质谱数据均符合要求。在构效关系研究中,将合成的hTGF-α类似物进行与A431细胞膜上的EGF受体竞争性结合的试验。以半抑制浓度(IC-50)为指标,发现Tyr^(38)及Arg^(42)二个残基对hTGF-α竞争性与EGF受体结合的活性具有突出的作用。
A number of hTGF-α analogues (1-11) were synthesized manually by stepwise solid-phase procedures on 0.6g of BOC-Ala-OCH2-Pam resin (substitution 0.3mmol/g of resin) for each analogue. After HF eleavage, and following dialysis (against 8-2 mol/L urea soln. in 24h.), refolding (disulfur bond formation for 24h.) and purification (by C-18 reverse phase HPLC), the pure peptides, with average yield of 2.9%, were characterized both by AAA and by MS. The bio-assay of binding to EGF receptor of human A431 cells with synthetic hTGF-α and its analogues (1-11) showed that the variations of Tyr38→(D)Tyr and Arg42→(D)Arg in hTGF-α sequence could dramatically reduce the original bioactivity to 1/5000 and 1/25000 respectively. While the variation of Tyr38→Ala, Arg42→Ala, Phe15→(D) Phe and Phe15→Ala just causes far less change of the original activity. Even no loss of activity was found in the variation of His35→Ala and Gly40→(D)Phe. Thus, the structure especially the configuration requirment at spot 38 and 42 was crucial to the bioactivity of hTGF-α.
