通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF-MS）分析重组CD24聚糖揭示唾液酸化-T抗原的普遍性。
Analysis of Recombinant CD24 Glycans by MALDI-TOF-MS Reveals Prevalence of Sialyl-T Antigen.
作者信息
Motari Edwin, Zheng Xincheng, Su Xiaodan, Liu Yang, Kvaratskhelia Mamuka, Freitas Michael, Wang Peng George
机构信息
Departments of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
出版信息
Am J Biomed Sci. 2009 Jan 1;1(1):1-11. doi: 10.5099/aj090100001.
CD24 is a glycosyl-phosphatidyl-inositol linked glycoprotein expressed in a broad range of cell types and is heavily glycosylated. It has been found to be over expressed in cancers and tumors and is also a costimulatory molecule. Therefore, this study was carried out to define the structures of the carbohydrates associated with the CD24 recombinant protein. The CD24 glycoprotein's oligosaccharides were released by chemical and enzymatic means prior to being analyzed by MALDI-TOF-MS. The results obtained showed that CD24 is both N- and O-glycosylated. The major oligosaccharides were found to be Neu5Acα-2,3/6Galβ-1,3GalNAc, NeuAc(2)Gal β-1,3GalNAc(1) (O-glycans), GalNAc(2)GlcNAc(2)Man(3)Fuc(1), Gal(1)GalNAc(2)GlcNAc(2)Man(3)Fuc(1), and Gal(2)GalNAc(2)GlcNAc(2)Man(3)Fuc(1) (N-glycans). The results showed that Neu5Acα-2,3/6Galβ-1,3GalNAc (sialyl-tumor antigen, sT), a cancer-associated carbohydrate, was the most abundant glycan associated with CD24. This result raised the intriguing possibility that CD24 may be a major carrier of the sialyl-T abundantly found in cancer cells.
CD24是一种糖基磷脂酰肌醇连接的糖蛋白，在多种细胞类型中表达，且糖基化程度很高。已发现它在癌症和肿瘤中过度表达，也是一种共刺激分子。因此，开展本研究以确定与CD24重组蛋白相关的碳水化合物结构。在通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF-MS）分析之前，通过化学和酶促方法释放CD24糖蛋白的寡糖。获得的结果表明CD24同时进行了N-糖基化和O-糖基化。发现主要的寡糖为Neu5Acα-2,3/6Galβ-1,3GalNAc、NeuAc(2)Gal β-1,3GalNAc(1)（O-聚糖）、GalNAc(2)GlcNAc(2)Man(3)Fuc(1)、Gal(1)GalNAc(2)GlcNAc(2)Man(3)Fuc(1)以及Gal(2)GalNAc(2)GlcNAc(2)Man(3)Fuc(1)（N-聚糖）。结果表明，Neu5Acα-2,3/6Galβ-1,3GalNAc（唾液酸化肿瘤抗原，sT），一种与癌症相关的碳水化合物，是与CD24相关的最丰富的聚糖。这一结果引发了一个有趣的可能性，即CD24可能是癌细胞中大量存在的唾液酸化-T的主要载体。
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