Interaction between Demineralized Dentin and HEMA

在此之前，我们已经报道了HEMA分子中酯部分的羰基与牙本质胶原相互作用。本研究采用~ 13 C NMR技术研究了HEMA与寡肽的相互作用<13>，以脯氨酸-羟脯氨酸-甘氨酸-脯氨酸-精氨酸-甘氨酸-脯氨酸-天冬氨酸-甘氨酸（Pro-Hyp-Gly-Pro-Arg-Gly-Pro-Asp-Gly）为模型化合物。将寡肽和HEMA溶解于0.600 g 20质量%的D_2O溶液中。用<13>EX 270光谱仪（JEOL）对HEMA和寡肽的13 C NMR自旋-晶格弛豫时间（T_1）进行了观察，发现在HEMA溶液中加入寡肽后，HEMA分子的T_1值降低。碳原子的T_1值降低的程度取决于碳原子核的类型。当寡肽溶液的pH值降低时，HEMA分子中羰基碳的T^1值降低。这反映了寡肽分子中天冬氨酸侧链上的羧基和C端的甘氨酸导致的羰基碳T_1值的降低，推测HEMA分子中的羰基与牙本质胶原大分子中氨基酸残基侧链上的羧基形成了氢键作用。

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.