【摘要】 目的比较重组类人胶原蛋白(RHCg)和牛源Ⅰ型胶原蛋白(BTCg)的异同。方法用有限胃蛋白酶水解和盐析沉淀法从牛肌腱中提取纯化BTCg。通过氨基酸分析测定BTCg和RHCg的氨基酸组成;用园二色谱表征BTCg和RHCg在溶液中变性前后的二级结构;用差示扫描量热仪(DSC)、调制差示扫描量热仪(MDSC)以及热重仪(TG)分析BTCg和RHCg的热学性质。结果RHCg和BTCg的氨基酸组成有显著差异。特别是RHCg不含羟脯氨酸;亚氨基酸含量为17.83%(残基数),低于BTCg的22.03%(残基数);赖氨酸含量为0.91%低于BTCg的2.37%;谷氨酸含量为8.13%低于BTCg的12.91%;精氨酸为1.01%低于BTCg的5.33%。在溶液中,温度为20℃时,BTCg和RHCg分子的二级结构均为左旋聚脯氨酸(P-Ⅱ)构型。BTCg和RHCg在140~280℃区间的热学性能显著不同。结论BTCg和RHCg分子的二级结构相似,但氨基酸组成和热学性质存在显著差异。充分认识和理解不同来源胶原蛋白质的特性对于合理设计和使用胶原基生物材料具有重要意义。更多还原

【Abstract】 PurposeIn an attempt to make a comparison between the collagens from E.coli expression and bovine tendon in terms of amino acid composition,secondary molecular conformation,and thermal properties.MethodsThe bovine tendon collagen type Ⅰ(BTCg) was isolated and purified by means of limited pepsin digestion and salt precipitation.Amino acid contents of both the recombinant human-like collagen(RHCg) and the BTCg were assayed by an amino acid analyzer.Molecular secondary structures of the RHCg and the BTCg in solution were examined using a circular dichroism(CD) before and after denaturation.Thermal behaviors of both were examined using a differential scanning calorimetry(DSC),a modulated DSC as well as a thermogravimetry analysis(TGA).ResultsThe RHCg had a significant different amino acid composition in comparison with that of the BTCg.Especially,for example,the former contained no hydroxyproline,a low percentage of imino acid(the RHCg,17.83% residue,the BTCg,22.03% residue),lysine(the RHCg,0.90% residue,the BTCg,2.37% residue),arginine(the RHCg,1.01% residue,the BTCg,5.33% residue),and glutamic acid(the RHCg,8.13% residue,the BTCg,12.91% residue).Molecular secondary structures of the RHCg and the BTCg both posed poly-L-proline conformation(P-Ⅱ) in solution at 20 ℃.The RHCg showed a different thermal behavior between 140-280 ℃ compared with that of the BTCg.ConclusionAlthough the RHCg and the BTCg were both in P-Ⅱ conformation in solution before denaturation,they had different amino acid compositions,and showed significant different thermal properties.Accordingly,thorough understanding the characteristic of collagens from different sources is of importance for "rational engineering" and application of collagen-based devices.更多还原