Alpha-2-macroglobulin (A2M) is a glycosylated broad spectrum inhibitor of numerous proteases, including those involved in blood coagulation. Glycosylation characteristics can affect protein structure and function. This study compares glycosylation characteristics of A2M in newborn umbilical cord (NUCP) and adult pooled plasmas. Peptide N-Glycosidase F treatment was used to evaluate the total N-glycan content of the molecules. Neuraminidase treatment, and affinity for Ricinus Communis Agglutinin I were used to examine terminal sialic acid and galactose content, respectively. Two-dimensional (2D) electrophoresis was used to determine charge-related isoform profiles and fluorophore-assisted carbohydrate electrophoresis (FACE) was used to characterize N-glycan profiles. Results revealed no difference in total N-glycan mass, however, a statistically significant difference was shown in the change in charge associated with sialic acid loss in the NUCP A2M population. 2D electrophoresis indicated a lower pI range for NUCP A2M isoforms. In addition, NUCP A2M displayed a trend toward higher terminal galactose quantities than adult A2M. FACE revealed an increased abundance of more branched, higher molecular weight glycans in NUCP A2M. These differences in glycan branching and charged residues may impact A2M receptor-based clearance and thus could be responsible for the increased A2M concentration seen in NUCP, and newborns.

中文翻译：

---

Alpha-2-巨球蛋白糖基化特征的年龄依赖性变化。

α-2-巨球蛋白（A2M）是多种蛋白酶（包括与血液凝固有关的蛋白酶）的糖基化广谱抑制剂。糖基化特性会影响蛋白质的结构和功能。这项研究比较了新生儿脐带（NUCP）和成人合并血浆中A2M的糖基化特征。肽N-糖苷酶F处理用于评估分子的总N-聚糖含量。神经氨酸酶治疗以及对蓖麻的亲和力凝集素I分别用于检查末端唾液酸和半乳糖含量。使用二维（2D）电泳确定与电荷相关的同工型谱，并使用荧光团辅助碳水化合物电泳（FACE）表征N-聚糖谱。结果显示总N-聚糖质量没有差异，但是，NUCP A2M人群中与唾液酸损失相关的电荷变化在统计学上具有显着差异。2D电泳显示NUCP A2M亚型的pI范围较低。另外，NUCP A2M显示出比成人A2M更高的最终半乳糖量的趋势。FACE显示NUCP A2M中更多的分支，更高分子量的聚糖含量增加。