Alteration of site-directed sugar chains of α_1-acid glycoprotein in serum of patients and its clinical significance

比较研究了健康人与炎症患者血清中α_1-酸性糖蛋白（AGP）的n -聚糖（clinchinacta, 2003）。用唾液酸酶处理纯化AGP后释放的n -聚糖，并进行MALDI-TOFMS分析。两组的n -聚糖均由双、三、四天线络合物组成，α - 1-3浓缩的n -聚糖含量为双、三、四天线络合物。在炎症患者中，双触角蛋白增加，三、四触角蛋白减少，α - 1-3聚焦化显著增加。分别比较AGP中5个糖基化位点的n -聚糖（制备中）。用内肽酶Glu-C对纯化的AGP进行处理，反相高效液相色谱分离得到的每个糖肽的n -聚糖用MALDI-TOFMS测定。每个糖基化位点由不同的和特征的天线聚糖组成，二、三链位点1和2，三、四链位点3至5。在所有糖基化位点均可见到更多的双触角蛋白增加，三、四触角蛋白减少，α_1-3聚焦化增加，急性炎症的程度大于慢性炎症。为了确定n -聚糖的癌变，研究了人肝癌细胞系HuH7和HepG2分泌的糖蛋白的n -聚糖（肛门科学，2003）。HepG2细胞分泌的几种糖蛋白中，三、四天线和α - 1-3聚焦化显著增加。此外，HepG2对NeuAcα2-3Galβ1-4GlcNAc-R的α1-3聚焦活性比HuH7高20倍。为了阐明高度聚焦的n -聚糖的生物学作用，我们将NK细胞刺激在从HepG2培养基中纯化的高度聚焦的糖蛋白包被的板上（未发表的结果）。高度集中的糖蛋白会调节NK细胞的功能，因为含有17kDa的蛋白被刺激磷酸化其酪氨酸残基。进一步的研究正在进行中。少

N-Glycans of α_1-acid glycoprotein (AGP) in sera of healthy individuals and patients with inflammation were comparatively studied (Clin Chim Acta, 2003). N-Glycans released from purified AGP with N-glycanase were treated with sialidase and subjected to MALDI-TOFMS analysis. N-Glycans of both groups were composed with bi-, tri-and tetra-antennary complex-types and the contents of α1-3 fucosylated N-glycans were bi-□tri-<tetra-antennary. In inflammation patients, increases in bi-antennary, decreases in tri-and tetra-antennary and increases in α1-3 fucosylation were significant.N-Glycans of 5 glycosylation sites in AGP were separately compared (in preparation). Purified AGP was treated with endopeptidase Glu-C and N-glycans of each glycopeptides isolated by a reversed phase HPLC were determined by MALDI-TOFMS. Each glycosylation site was composed with different and characteristic antennary glycans, bi-and tri-in sites 1 and 2 and tri-and tetra-antennary in sites 3 to 5. In inflammatory, i … More ncreases in bi-antennary, decreases in tri-and tetra-antennary and increases in α_1-3 fucosylation were commonly observed in all glycosylation sites, in larger degrees in acute than chronic inflammation.To determine cancerous alteration of N-glycans, N-glycans of glycoproteins secreted from human hepatoma cell lines HuH7 and HepG2 were studied (Anal Sci, 2003). Increases in tri-and tetra-antennary and α1-3 fucosylation were prominently detected in several glycoproteins secreted by HepG2 cells. Moreover, α1-3 fucosylation activities toward NeuAcα2-3Galβ1-4GlcNAc-R were detected 20-fold highly in HepG2, comparing to HuH7.To clarify the biological roles of high-fucosylated N-glycans, NK cells were stimulated on plates coated with high-fucosylated glycoproteins purified from HepG2 culture, medium (unpublished result). High-fucosylated glycoproteins will modulate the NK cell functions, since protein with 17kDa was stimulated to phosphorylate on its tyrosine residues. Further study is in progress. Less