Facile synthesis of pH-responsive glycopolypeptides with adjustable sugar density
Facile synthesis of pH-responsive glycopolypeptides with adjustable sugar density
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DOI：
10.1002/pola.26796
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发表时间：
2013-09-15
影响因子：
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通讯作者：
Menzel, Henning
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文献类型：
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作者：
Mildner, Robert;Menzel, Henning
以4-（4，6-二甲氧基-1，3，5-三嗪-2-基）-4-甲基吗啉鎓氯化物（DMT-MM）为偶联剂，在无任何有机溶剂、添加剂或缓冲液的条件下，通过D-氨基葡萄糖与聚（α，L-谷氨酸）（PGA）的类似聚合物水溶液酰胺偶联制备了pH响应性糖多肽。取代度（DS）可达到80%，并且DS可通过DMT-MM与PGA重复单元的摩尔比来调节。通过H-1 NMR和FTIR光谱以及在低pH下的增强溶解度证实了低MW和高MW PGA的成功糖基化。CD光谱显示，DS高达0.63的糖基化PGA能够经历pH响应性和可逆的螺旋-卷曲转变。然而，对于具有较高DS的聚合物，没有发生转变。与用单乙醇胺官能化的PGA的比较表明，在高DS下的低螺旋度不是由于庞大的糖部分引起的空间效应，而是溶剂化效应。用凝集素伴刀豆球蛋白A进行的初步比浊试验表明这些糖基化多肽具有生物活性。(C)2013 Wiley Periodicals，Inc. J. Polym.科学，部分A：聚合物。2013，51，3925-3931
Well-defined pH-responsive glycopolypeptides were prepared by polymer-analogous aqueous amide coupling of D-glucosamine to poly(alpha,L-glutamic acid) (PGA) using the coupling agent 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) without any organic solvents, additives, or buffers. Degrees of substitution (DS) up to 80% can be achieved, and the DS is adjustable by the molar ratio of DMT-MM to PGA repeating units. Successful glycosylation of both low MW and high MW PGA was confirmed by H-1 NMR and FTIR spectroscopy as well as by an enhanced solubility at low pH. CD spectroscopy revealed that glycosylated PGAs with a DS up to 0.63 are able to undergo a pH-responsive and reversible helix-coil transition. However, for polymers with higher DS no transition occurs. A comparison with PGAs functionalized with monoethanolamine showed that the low helicity at high DS is not a steric effect due to the bulky sugar moieties, but a solvation effect. Preliminary turbidimetric tests with the lectin Concanavalin A indicate a biological activity of these glycosylated polypeptides. (C) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3925-3931