Glycan Labeling for Negative-Ion MS/MS Branch Analysis
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Solution Overview
Problem
Conventional glycan analysis methods require costly and complex preprocessing, such as using expensive special matrices and limited mass spectrometers, to achieve negative ionization and obtain MS/MS spectra reflecting branched structural information, which is not suitable for general-purpose analysis.
Innovation Solution
A method involving labeling glycans without reduction using acidic or basic labeling agents that can stably present a negative charge, followed by MS/MS analysis in negative ion mode, allowing for the observation of branched structure-specific product ions without the need for special matrices or mass spectrometers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional negative ionization methods using special matrices are used, then branched structural information can be obtained, but the preprocessing becomes costly and complex
Solution Approach 1:
The patent replaces expensive special matrices (like G3CA) with inexpensive, readily available matrices (such as DHB, CHCA, or sinapinic acid). This allows general laboratories to perform negative ionization without requiring specialized consumables, thereby reducing preprocessing complexity and cost while maintaining the ability to obtain branched structural information through MS/MS analysis
Solution Approach 2:
The patent changes the ionization mode parameter from positive to negative ion mode in mass spectrometry. This parameter change enables the observation of branched structure-specific product ions (such as D ions and E ions in N-linked glycans) that are not visible in positive ion mode, thereby obtaining branched structural information using conventional matrices and equipment
2Measurement precision
If special matrices are used for negative ionization, then MS/MS spectra reflecting branched structure can be acquired, but general-purpose analysis is not enabled
Solution Approach 1:
The patent makes the mass spectrometry method universally applicable by using conventional matrices that are already present in most laboratories. The method can analyze both branched and linear glycans, and works with various glycan types (N-linked, O-linked, etc.), thereby enabling general-purpose structural analysis without requiring specialized equipment or consumables
3Quantity of substance
If positive ion mode is used for mass spectrometry, then monosaccharide composition can be estimated, but branched structure information is lost
Solution Approach 1:
The patent inverts the conventional approach by using negative ion mode instead of positive ion mode for mass spectrometry analysis. In negative ion mode, the dissociation pattern changes such that branched structure-specific product ions (D ions reflecting 1-6 arms and E ions reflecting 1-3 arms) are generated and detected, thereby recovering the branched structure information that is lost in positive ion mode while still allowing monosaccharide composition estimation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables efficient and cost-effective negative ionization of glycans, allowing for the acquisition of MS/MS spectra reflecting branched structural information using general preprocessing and equipment, facilitating the estimation of glycan structures with branched structures.
Implementation Method 1
a sample preparation step of preparing a sample by labeling glycan to be analyzed without reduction, using a labeling agent having at least one site capable of stably presenting a negative charge in a molecule
Implementation Method 2
an analysis execution step of subjecting the sample to MS/MS analysis in negative ion mode
Data Source
AI summary
Glycans having a branched structure are labeled with a labeling agent, such as 2-aminobenzoic acid, having one site that is easily negatively charged. At this time, reduction which is usually performed in labeling by reduction amination is not performed. A sample for mass spectrometry containing the labeled form of glycans thus obtained is prepared, and is subjected to MS/MS analysis in negative ion mode. In the MS/MS spectra obtained by the MS/MS analysis, peaks of E ions, D ions and the like which reflect the branched structure clearly appear. As a result, structural analysis of an entirety of the glycan including the branched structure can be easily performed.