Panzironi C, Silvestrini B, Mo M Y, Lahita R, Mruk D, Cheng C Y
The Population Council, New York, NY 10021, USA.
Biochem Mol Biol Int. 1997 Dec;43(6):1305-22. doi: 10.1080/15216549700205131.
Using lectin blots in conjunction with peptide mapping, alpha 2-macroglobulin micropurified from systemic lupus erythematosus (SLE) patients was shown to become abnormally glycosylated suggesting the occurrence of complex glycosylation in this pathological condition. To confirm there is indeed a quantitative increase in specific monosaccharides in this protein; alpha 2-macroglobulin was micropurified from a battery of 37 serum samples which included 6 normal donors (3 male and 3 female), 23 SLE patients, 6 rheumatoid arthritis patients, 1 mixed connective tissue disease patient, and 1 Sjogren's syndrome patient; for carbohydrate analysis. It was noted that the concentration of total monosaccharides in alpha 2-macroglobulin micropurified from serum samples of SLE patients is significantly higher than normal donors with a mean +/- SD of 188 +/- 410 micrograms/mg protein (SLE, n = 23) versus 14.5 +/- 4 micrograms/mg protein (normal, n = 6) even though there was a high variation in the level of monosaccharides among the SLE patients. An increase in oligosaccharides in alpha 2-macroglobulin from SLE patients compared to normal subjects was confirmed by concanavalin A (Con A) blots using peptide fragments derived from the micropurified protein. Since the interaction of peptide fragments derived from alpha 2-macroglobulin with Con A requires the presence of mannose and/or glucose residues, we have also examined if there are any correlations between the levels of mannose and glucose in alpha 2-macroglobulin and SLE. The concentration of mannose (38 +/- 60 micrograms/mg protein) in alpha 2-macroglobulin derived from SLE patients was significantly higher than normal donors (mannose, 4.8 +/- 1 micrograms/mg protein) however, the concentration of glucose in alpha 2-macroglobulin derived from SLE patients when compared to normal donors was not statistically significant, 18 +/- 20 micrograms/mg protein in SLE versus 2 +/- 0.5 micrograms/mg protein in normal donors due to high variation between samples. Also, the concentration of galactose in alpha 2-macroglobulin from SLE patients was significantly higher than normal donors (45.7 +/- 173 micrograms/mg protein versus 0.13 +/- 0.03 microgram/mg protein). These results illustrate quantification of carbohydrate in selected glycoproteins such as alpha 2-macroglobulin may be a novel and alternative clinical marker for SLE.
通过结合凝集素印迹法和肽图谱分析，发现从系统性红斑狼疮（SLE）患者体内微纯化得到的α2-巨球蛋白发生了异常糖基化，这表明在这种病理状态下出现了复杂糖基化。为了证实该蛋白中特定单糖确实存在定量增加；从37份血清样本中微纯化α2-巨球蛋白，这些样本包括6名正常供体（3名男性和3名女性）、23名SLE患者、6名类风湿性关节炎患者、1名混合性结缔组织病患者和1名干燥综合征患者；用于碳水化合物分析。值得注意的是，从SLE患者血清样本中微纯化得到的α2-巨球蛋白中总单糖浓度显著高于正常供体，SLE患者的平均值±标准差为188±410微克/毫克蛋白（n = 23），而正常供体为14.5±4微克/毫克蛋白（n = 6），尽管SLE患者中单核糖水平存在很大差异。使用从微纯化蛋白衍生的肽片段进行伴刀豆球蛋白A（Con A）印迹法，证实了与正常受试者相比，SLE患者α2-巨球蛋白中寡糖增加。由于源自α2-巨球蛋白的肽片段与Con A的相互作用需要甘露糖和/或葡萄糖残基的存在，我们还研究了α2-巨球蛋白中甘露糖和葡萄糖水平与SLE之间是否存在任何相关性。源自SLE患者的α2-巨球蛋白中甘露糖浓度（38±60微克/毫克蛋白）显著高于正常供体（甘露糖，4.8±1微克/毫克蛋白），然而，与正常供体相比，源自SLE患者的α2-巨球蛋白中葡萄糖浓度无统计学意义，SLE患者为18±20微克/毫克蛋白，正常供体为2±0.5微克/毫克蛋白，因为样本间差异很大。此外，SLE患者α2-巨球蛋白中半乳糖浓度显著高于正常供体（45.7±173微克/毫克蛋白对0.13±0.03微克/毫克蛋白）。这些结果表明，对选定糖蛋白（如α2-巨球蛋白）中的碳水化合物进行定量分析可能是SLE一种新的替代临床标志物。
