α-氨基酸及其酯化物侧链对其β-环糊精复合物稳定常数的影响

发布时间：2018-03-26 06:12

本文选题：β-环糊精复合物　切入点：α-氨基酸及其酯化物侧链　出处：《高等学校化学学报》2017年05期

【摘要】：为了探索α-氨基酸及其酯化物的侧链R基团对其与环糊精非共价复合物结合强度的影响,将一定摩尔比的β-环糊精(β-CD)分别与L型正缬氨酸(n-Val)、亮氨酸(Leu)、苯丙氨酸(Phe)、天冬氨酸(Asp)、天冬氨酸-4-苄酯(Asp-4-benzyl ester)和天冬氨酸-4-叔丁酯(Asp-4-t-butyl ester)在室温下混合,反应平衡后采用电喷雾电离质谱进行竞争反应检测,并以改进的质谱滴定结合曲线拟合法计算结合常数.结果表明,它们均可形成摩尔比为1∶1的非共价复合物.在2组竞争反应中,复合物的结合强度顺序分别为[β-CD∶Asp-4-benzyl ester+H]~+[β-CD∶Asp-4-t-butyl ester+H]~+[β-CD∶Asp+H]~+以及[β-CD∶Phe+H]~+[β-CD∶Leu+H]~+[β-CD∶n-Val+H]~+.质谱滴定曲线拟合法测得[β-CD∶n-Val+H]~+,[β-CD∶Asp+H]~+,[β-CD∶Asp-4-t-butyl ester+H]~+,[β-CD∶Asp-4-benzyl ester+H]~+,[β-CD∶Leu+H]~+和[β-CD∶Phe+H]~+的稳定常数(lgK_(st))分别为1.81,2.54,3.14,3.26,3.36和3.67,结合强度依次增强.竞争反应的定性分析结果与质谱滴定定量法测得结合强度结果的趋势一致.由于所选用的α-氨基酸及其酯化物客体的羧基端(—COOH)和氨基端(—NH_2)均相同,且都为亲水基团,仅有侧链R基团不同,因此在溶液中客体分子受疏水驱动与β-CD主体靠近并结合时,侧链R基团的疏水力和极性2个因素起重要作用.由于客体分子体积小,其碳端的羧基还可与β-CD大口或小口边缘的羟基形成氢键,使复合物更加稳定.
[Abstract]:In order to explore the effect of side chain R group of 伪 -amino acid and its ester on the binding strength of 伪 -amino acid and its side chain R group to cyclodextrin noncovalent complex, 尾 -cyclodextrin (尾 -CD) was mixed with L-type valine n-Valan, leucine leucine, phenylalanine Phehe, Asp-4-benzyl aspartate, Asp-4-benzyl esterat and Asp-4-t-butyl esterat at room temperature, respectively. After reaction equilibrium, the competitive reaction was detected by electrospray ionization mass spectrometry, and the binding constant was calculated by the improved mass spectrometry titration and curve fitting method. They all form noncovalent complexes with a molar ratio of 1:1. In two groups of competitive reactions, The order of binding strength of the complexes is [尾 -CDAsp-4-benzyl ester H] ~ [尾 -CD: Asp-4-t-butyl ester H] ~ [尾 -CDAsp-4-butyl ester H] and [尾 -CDAsp-4-benzyl ester H] ~ ~ [尾 -CDAsp-4-benzyl ester H] ~ ~ [尾 -CDAsp-4-benzyl ester H] ~ [尾 -CDAsp-4-benzyl ester H] and [尾 -CDAsp-4-benzAsp H] ~, [尾 -CDAsp-4-benzAsp H] and [尾 -CDPHE H] ~ and [尾 -CDPHE H] and [尾 -CDPHE H] and [尾 -CDAsp-4-benzyl ester H] ~, [尾 -CDAsp-4--butyl ester H], [尾 -CDAsp-4-benzyl ester H], [尾 -CDAsp-4-benzyl ester H], [尾 -CDAsp-4-benzyl ester H] and [尾 -CDPHE H] and [尾 -CDPHE H] and 尾 -CDPHE H respectively. The results of qualitative analysis of the competitive reaction were consistent with the results obtained by quantitative mass spectrometry titration. Because the 伪 -amino acid and its ester guest carboxyl terminal (COOH) and amino terminal (NH2) were the same, They are hydrophilic groups, only the side chain R groups are different, so the hydrophobic force and polarity of the side chain R group play an important role when the guest molecules are driven by hydrophobic force and bound to 尾 -CD host in solution. The carboxyl group of the carbon terminal can also form a hydrogen bond with the hydroxyl group at the big or small mouth edge of 尾 -CD, which makes the complex more stable.
【作者单位】：复旦大学化学系激光化学研究所;
【基金】：国家十二五重大科学仪器专项(批准号:2011YQ14015006)资助~~
【分类号】：O636.12;O657.63

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