Detection Of Choline Derivants In Serum By NMR Spectroscopy

Blood serum contains many important nutrient contents such as inorganic salt, lipoproteins, amino acids, carbohydrates, proteins, and is an important biological fluids that has many important functions, for transporting nutritive material, conditioning body fluid, maintaining homeostasis and preventing hazardous substances and so on. Therefore, metabolite profiling of blood serum provides not only a view of the over all state of a people’s health, but also information for clinical diagnostics.Lipoproteins are a class of the key components in serum, and it was found that the composition of lipoproteins, especially the variation contents of phosphatidylcholine (PC) and sphingomyelin (SM) were closely related to many diseases. Therefore, analysis the relative amount of those choline derivatives (PC and SM) has important implications on the function of lipoproteins and their relationship with some important diseases.NMR can detect many different substances simultaneously without sample separation, and plays an important role in serum profiling. However, NMR detection of these choline derivants are usually difficulty because of their broad line width and overlap with each other, and with NMR peaks of the other components.In this dissertation,2D1H-14N heteronuclear single quantum correlation (HSQC) experiment has been used to detect PC and SM in serum selectively, in order to eliminate the background signal from other metabolites, the results showed as follows:1. We have detected four different-N+(CH3)3signals selectively in serum using1H-14N HSQC, and were found that they came from PC and SM located in inner part and surface of the lipoprotein particles, respectively. The result indicates that this technology can distinguish PC and SM signals effectively and simply. Therefore, this technology provides much convenience way for the analysis PC and SM contents in lipoprotein.2. The technology has also been used for the further study of the interaction between lipoproteins and ibuprofen (IBP), and the interaction between lipoproteins and cholesterol. It was found that both IBP and cholesterol affects the structure of lipoproteins, and IBP may have priority interaction with SM. This result may help us understand the function of lipoproteins.3. Quantitative detections of PC and SM have also been attempted using this technology.