Large-Scale Measurement of Absolute Protein Glycosylation Stoichiometry

Protein glycosylation is one of the
most important protein modifications.
Glycosylation site occupancy alteration has been implicated in human
diseases and cancers. However, current glycoproteomic methods focus
on the identification and quantification of glycosylated peptides
and glycosylation sites but not glycosylation occupancy or glycoform
stoichiometry. Here we describe a method for large-scale determination
of the absolute glycosylation stoichiometry using three independent
relative ratios. Using this method, we determined 117 absolute N-glycosylation
occupancies in OVCAR-3 cells. Finally, we investigated the possible
functions and the determinants for partial glycosylation.

蛋白质糖基化是蛋白质修饰中最为关键的环节之一。糖基化位点占据率的改变已被证实与人类疾病及癌症的发生密切相关。然而，现有的糖蛋白组学方法主要集中于糖基化肽段及糖基化位点的鉴定与定量，却未能深入探究糖基化占据率或糖苷形化学计量比。本研究中，我们描述了一种基于三个独立相对比率的绝对糖基化化学计量比的大规模测定方法。通过此方法，我们确定了OVCAR-3细胞中117个绝对N-糖基化占据率。最终，我们对部分糖基化的潜在功能及其决定因素进行了深入探讨。