| The liver is one of the main organs for synthesis protein in the body, when liver lesions occur within the tissue the N-glycan will also have a series of changes in the content and structure.However, it is not enough comprehensive and in-depth in the structure of N-glycan about the liver proteins.C57 mouse and SD rats is similar to human in physiological and biochemical characteristics most and is of great significance in the study of the liver as two kinds of animal models. Therefore, this study used PNGase F in releasing these two kinds of N-glycan from C57 mouse and SD rats liver respectively, and followed by composition analysis through ESI-MS.Then using method of stable isotope labeling combined with ESI-MS in equivalent mole to two kinds of the N-glycan of total protein in the liver in order to having relative quantitative analysis. Finally, the HILIC-MS and MS/MS were used to the separation and identification to the structure of N-glycan derivatived from C57 mice and SD rats and their relative abundance in the quantitative comparison.The conclusions show that:(1)、In C57 mices, we found a total of 16 N-glycans. there are two of truncated structure (shortened structure),7 are high mannose type structure, the 4 are complex type and 3 are hybrid type, respectively accounted for 12.5%,6.25%,37.5%,25%, 37.5% of total N-glycan. In SD rats, a total of 16 N-glycan too. But two of truncated structure (shortened structure),7 are high mannose type structure, the 5 are complex type and 2 are hybrid type, respectively accounted for 12.5%,6.25%,37.5%,31.25% and 12.5%. fucosglycosylation of N-glycan accounted for 18.75% of the total N-glycan.(2)、From the abundance ratio of SD rats and C57 mice:0.33,0.31,0.29,0.81, 0.36,0.34,0.38,0.43,0.49,0.37,0.53,0.72,0.51,0.82,0.49,0.17,0.39, we can infer that, the N-glycan expressed in the C57 mouse liver is much higher than SD rats, and up to 9.37 times.2、The protein in Erythrocyte Membrane system mostly for glycoprotein, and in which the modified glycan could regulat the red blood cells to various life activities. this study we using the ESI-MS to analysis and compare Erythrocyte membrane N-glycans from three kinds of model animals(C57 mouse、SD rats and rabbit):There are 6 [M+Na]+-glycans in C57 mouse erythrocyte membrane:H9N2, H3N6, H5N2, H6N2, H7N2, H8N2, among them, one for complex, the remaining five are all high mannose type. SD rats including two [M+2Na]2+ in the form of N-glycans:H9N2, H3N6; five were [M+Na]+:H5N2, H6N2, H7N2, H8N2, H9N2, and all of them are high mannose type. In total,20 N-glycans are found in Rabbit erythrocyte membrane:H4N4, H5N2, H4N3, H6N2, H5N3, H4N4, H7N2, H6N3, H5N4, H8N2, H6N4, H9N2, H7N4, H2N2Fuc, H3N2Fuc, H4N3Fuc, H5N3Fuc, H6N3Fuc, H5N4Fuc, H6N4Fuc,which contains 1 truncated structure,6 high mannose type, two complex and 11 hybrid type, accounted for 5%,30%,10%,55% of total glycan group. The results showed that high mannose type in C57 mice N-glycan accounted for 83% of its total glycan group,SD rats was 100% and the rabbit high mannose type accounts for only 30%. But these two N-glycans from C57 mice and SD rats on the quantity and the complexity are far below the rabbit erythrocyte membrane N-glycans. Due to little sialylated glycan in erythrocyte membrane and was not detected in the ESI-MS. |
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