Interaction between Demineralized Dentin and HEMA

此前，我们曾报道HEMA分子中酯部分的羰基与牙本质胶原相互作用。在本研究中，为了确定HEMA分子中的羰基吸附的胶原功能，用~(13)C核磁共振技术研究了HEMA与寡肽的相互作用细节。将寡肽和HEMA溶解于0.600 g质量分数为20%的D_2O溶液中。用EX270型能谱仪(JEOL)对HEMA和寡肽的自旋-晶格驰豫时间T_1进行了观察，结果表明，在HEMA溶液中加入寡肽后，归属于HEMA分子的碳的T_1值降低。碳的T_1值下降的程度取决于碳核的类型。当低聚肽溶液的pH值降低时，HEMA分子中的羰基碳的T^1值降低。这反映了寡肽分子中天冬氨酸侧链和C端甘氨酸侧链上的羧基所致的羰基T_1值的降低。我们认为HEMA分子中的羰基与牙本质胶原大分子中氨基酸残基的侧链上的羧基形成了氢键相互作用。

Previously, we had reported that the carbonyl group of the ester portion in the HEMA molecule interacted with the dentinal collagen. In this study, in order to identify the collagen function where the carbonyl group in the HEMA molecule adsorbed, the details of the interaction between HEMA and oligopeptide were investigated by using the ^<13>C NMR technique.The oligopeptide used as a model compound for the collagen consists of Pro-Hyp-Gly-Pro-Arg-Gly-Pro-Asp-Gly. The oligopeptide and the HEMA were dissolved into 0.600 g of 20 mass% D_2O solution. The ^<13>C NMR spin-lattice relaxation time, T_1, observation of the carbons attributed to the HEMA and the oligopeptide was conducted both alone and in the presence of them using an EX270 spectrometer (JEOL).The addition of the oligopeptide to the HEMA solution resulted in a decrease in the T_1 value of the carbons assigned to the HEMA molecule. The degree of the decrease in the T_1 value of the carbons was dependent upon the types of carbon nuclei. When the pH value of the oligopeptide solution was decreased, the T^1 value of the carbonyl carbon in the HEMA molecule decreased. Which reflecting the decrease in the T_1 value of the carbonyl carbons attributed to the carboxylic acid group of the side chain of the Asp and the C-terminal Gly in the oligopeptide molecule.We conclude that the carbonyl group in the HEMA molecule would form a hydrogen bonded interaction with the carboxylic acid group of the side chain of the amino acid residue in the dentinal collagen macromolecule.