OH RADICAL OXIDATION DURING ESI

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。我们对开发质谱方法来跟踪和揭示生物材料的化学特性很感兴趣。我们希望“就地”进行，也就是说，在进行MALDI或ESI的过程中。自由基损伤是一个领域，相当多的推论证据指出自由基损害DNA和蛋白质的后果。我们认为，通过在电喷雾源中进行破坏性化学反应，可以获得生物材料与自由基反应性的直接证据。为此，我们正在构建一种特殊的离线ESI源，可以将自由基与肽和蛋白质一起喷射。在收集喷雾后，我们计划通过第二次ESI实验，结合MS/MS，或MALDI和PSD或MS/MS来分析“斑点”。初步数据表明，该方法是可行的，我们能够生成OH自由基，并与各种肽和小蛋白质反应。我们打算继续这一发展，作为一般策略的一部分，在质谱中使用现代电离方法作为确定化学和生化反应性的手段，并作为跟踪相互作用和构象变化的手段。我们还在考虑一种结合涡流的装置，以帮助进行反应，并更好地聚焦电喷雾产生的离子。

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. We are interested in developing mass spectral methods to follow and uncover chemistry of biological materials. We wish to do this "in-situ;" that is, in the process of conducting MALDI or ESI. Free radical damage is one area where considerable inferential evidence points to the consequences of free radicals in damaging DNA and proteins. We believe that direct evidence of reactivity of biological material with free radicals could be gained by conducting the damaging chemical reactions in the electrospray source. To this end, we are constructing a special off-line ESI source where free radicals can be sprayed together with peptides and proteins. Following collection of the spray, we plan to analyze the "spot" by either a second ESI experiment, coupled with MS/MS, or by MALDI and either PSD or MS/MS. Preliminary data show that the approach is feasible and that we are able to generate and react OH radicals with various peptides and small proteins. We intend to continue this developm ent as part of a general strategy to use contemporary ionization methods in MS as means for determining chemical and biochemical reactivity and as means of following interactions and conformation change. We are also considering a device incorporating vortex flows to help conduct the reactions and also to better focus the ions produced by electrospray.