USE OF 18O LABELS TO MONITOR DEAMIDATION DURING SAMPLE PROCESSING

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 在样品处理过程中，特别是使用典型的胰蛋白酶消化方案时，脱酰胺可能作为人为因素发生。我们已经开发了一种18 O标记的方法来监测这些人工脱酰胺，其中酶消化在18 O标记的水中进行。虽然体内脱酰胺导致每个脱酰胺位点的+1 Da质量偏移（由于-NH 2基团被-OH基团取代），但消化过程中发生的那些导致+3 Da质量偏移，额外的+2 Da由一个18 O原子的掺入产生。这项研究最近发表（Li et al.，2008）在Journal of the American Society for Mass Spectrometry，2008，19，855-864中。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Deamidation may occur as an artifact during sample processing, particularly when using typical tryptic digestion protocols. We have developed an 18O labeling approach to monitor these artificial deamidations, where the enzymatic digestion was carried out in 18O labeled water. While in vivo deamidation causes a +1 Da mass shift per deamidation site due to the substitution of the -NH2 group by the -OH group, those occurred during digestion lead to a +3 Da mass shift, with the extra +2 Da arising from the incorporation of one 18O atom. This study has recently been published (Li et al., 2008) in the Journal of the American Society for Mass Spectrometry, 2008, 19, 855-864.