Identity^E High Definition Proteomics™系統定義了嚴格的蛋白質鑑定的新標準。Waters解決方案其設計用於權威性及全面性之定性分析，可讓蛋白質體學研究人員參考層析滯留時間、先導離子及子離子質量、結構意義、生物背景及多種胜肽似是而非的偵測性，以確信地進行蛋白質鑑定。

Identity^E系統係針對複雜的蛋白質消化之定性分析而設計，利用UPLC^®離析上的優異的解析度及MS^E新穎的方法，為您提供傑出的層析結果，並同時取得前驅物離子及產物離子資訊。

系統包括全方位的胜肽離子計數資訊方式，以蛋白質主要結構之多層次物理化學模式來協助您視覺化並辨識胜肽及蛋白質，以產生最高品質的MRM轉換，以便進行串聯式四極桿生物標記的確認與驗證工作。

Identity^E High Definition蛋白質體學系統架構：

• nanoACQUITY UPLC^®系統
• Synapt™ High Definition MS™系統或Q-Tof Premier™質譜儀
• MS^E 資料擷取及動態質量解析度。
• 高蛋白質序列覆蓋率之全面性胜肽離子計數資訊學，讓您可以最低的誤判率來辨識多數的蛋白質。
• ProteinLynx GlobalSERVER™軟體
• 訓練及支援，包括線上課程

Identity^E系統可提供完整的內容相關資訊，作為極具信心的蛋白質辨識之用，可以引領更可期的生物及醫療研究。此包括尋求在定性上蛋白質鑑定更佳的再現性及可靠性的實驗室，諸如：

• 大學生物／生物化學系
• 核心蛋白質體實驗室
• 癌症研究機構
• 蛋白質功能／相互反應實驗室
• 生物科技公司
  

Identity^E High Definition Proteomics^TM系統結合UPLC^®/MS^E資料及全面性的胜肽離子計數資訊學解決方案，將複雜的蛋白質消化混合體進行編列。系統特色包括：

動力調整的蛋白質消化步驟，可將未被酵素切斷的胜肽見到最少

使用大略2μm以下的乙基架橋混合物(BEH)顆粒管柱於nanoflow UPLC分離，可提供前所未有的波峰容量及滯留時間重複性

UPLC波峰容量及可靠性可強調出Identity^E系統滯留時間預測模式的特異性，可以驗證從MS^E質譜鑑定得到的胜肽胺基酸組成證實

高解析度質量分析利用動態質量解析度及頻寬可進行胜肽偵測，確保複雜蛋白質消化樣品的一致性過度取樣

Identity^E經由Expression^E系統可擴充至免標定蛋白質生物標記研究的相對及絕對定量研究

Data Acquisition by Alternating Spectra Energy

UPLC-MS^E is a unique, patented technology that has an extremely high duty cycle, allowing the acquisition of high quality accurate mass data in a simple, unbiased manner.

UPLC/MS^E acquires data with two rapidly alternating MS functions. The first contains exclusively low-energy mass spectra, the second is composed of mass spectra acquired at elevated collision energy (designated as MS^E). The resulting data set contains a comprehensive time-resolved record of all detectible precursor and product ions.

Precursor and product ions are associated by both retention time alignment and peak shape, enabling even chimeric peptides and overlapping ion clusters to be successfully handled. The resulting time-aligned precursor and product ion mass lists are used for peptide identification with the Identity^E System's peptide ion informatics.

Peptide Ion Informatics

This bioinformatics software visualizes peptides and proteins with a new multi-layered physicochemical model of protein primary structure. Peptide ion accounting informatics adapts to each new UPLC/MS^E data set using a pre-assessment survey. 250 identified peptides, per run, are used to fine-tune many of the 14 models used for both peptide and protein authentication.

After pre-assessment, an iterative database search strategy is initiated, identifying the most abundant protein within a sample by matching peptides, modified peptides, and retention times. An estimate of the absolute concentration of each protein is made by reference to an internal (protein) standard, allowing the fractions of all theoretical tryptic peptides that are plausibly detectable to be predicted. Proteins identified with fewer than the predicted number of peptides are sequence mapped for evidence of C/N-terminal processing.

When the most abundant protein is conclusively identified, all assigned peptide ions are subtracted from the working image of the data.

Multi-layered Physicochemical Model

The Identity^E system features Waters peptide ion accounting informatics. This technology visualizes peptides and proteins with a multi-layered physicochemical model of protein primary structure, developed from a post-genomic understanding of protein characteristics - an advantage unavailable in any other protein identification tool and unique to the Identity^E system.

Pre-assessment survey

Peptide ion accounting informatics adapts to each new UPLC/MS^E data set utilizing a pre-assessment survey. 250 unambiguously identified (abundant) peptides, per run, are used to fine-tune many of the 14 models used for both peptide and protein authentication. Automatic adjustment of these models on an injection-by-injection basis provides the means for the software to handle changes in chromatographic conditions (buffers and columns), enzymatic specificity, and sample complexity.

Fourteen different physicochemical attributes are automatically considered to maximize peptide identification confidence. Other conventional protein identification systems utilize only a small number of these characteristics.

Iterative Protein Identification

When the most abundant protein is conclusively identified, all assigned peptide ions are subtracted from the working image of the data. The process is then repeated for the next most abundant protein, as many times as is necessary to account for as many ions as possible within the UPLC/MS^E data set. As more proteins are identified, and their associated peptide ions are removed, the working image of the data becomes less complex - revealing proteins of decreasing abundance for identification.

Utilizing the 14 physicochemical models of the peptide ion accounting informatics, proteins are identified in order of their abundance, thus increasing the selectivity, specificity, and sensitivity of each iterative protein identification. The above data illustrates that proteins are being identified and their respective ions depleted by their abundance.

More Peptides per Protein

The Identity^E System identifies more peptides per protein, providing both higher sequence coverage and rigor to the protein ID. Over 95% (389) of the proteins were identified with greater than three peptides to match, compared to the LTQ Orbitrap and the LTQ with only 65% (244) and 33% (88), respectively.

More Peptides per Protein

The Identity^E System identifies more peptides per protein, providing both higher sequence coverage and rigor to the protein ID. Over 95% (389) of the proteins were identified with greater than three peptides to match, compared to the LTQ Orbitrap and the LTQ with only 65% (244) and 33% (88), respectively.