Glycan Sample Preparation for Accurate Sialic Acid Linkage Analysis

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Solution Overview

Problem

Current methods for analyzing sialic acid linkage types in glycans using mass spectrometry face challenges due to reduced reaction specificity, particularly in O-linked glycans, where α2,6-sialic acids are often lactonized unintentionally, leading to inaccurate differentiation of linkage types.

Innovation Solution

A method involving selective lactonization of α2,3-sialic acid and α2,6-sialic acid, followed by ring-opening of the lactone formed, and repeated cycles of these reactions, ensures accurate modification and differentiation of sialic acid linkage types by performing the reactions in a basic solvent with a pH of 8 or higher, often with the glycan bound to a solid phase carrier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If chemical derivatization methods are used to modify sialic acid in a linkage-specific manner, then the linkage type of sialic acid can be differentiated through mass spectrometry, but reaction specificity is reduced particularly in O-linked glycans causing unintentional lactonization of α2,6-sialic acids

Engineering Contradiction:
Improvelinkage type differentiation accuracyVSAvoidreaction specificity
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by performing a first reaction to selectively lactonize α2,3-sialic acid before subsequent analysis steps. This preliminary modification establishes a clear chemical distinction between linkage types early in the process, enabling accurate differentiation while maintaining reaction specificity through controlled selective lactonization conditions

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by adjusting reaction conditions including pH control (using buffers at specific pH ranges), temperature, and reagent concentrations to optimize selective lactonization. By carefully controlling these parameters, the method achieves high reaction specificity for α2,3-sialic acid while preventing unwanted side reactions with α2,6-sialic acid in O-linked glycans

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If sialic acid is stabilized by amidation in a non-aqueous solvent, then sialic acid is stabilized for mass spectrometry analysis, but sialic acids of different linkage types cannot be differentiated

Engineering Contradiction:
Improvesialic acid stabilityVSAvoidlinkage type differentiation
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The patent applies local quality by implementing linkage-specific modification where only sialic acids with particular linkage types (α2,3-) undergo lactonization, while others (α2,6-) remain unmodified or undergo different modifications. This creates localized chemical differences at specific linkage positions, enabling mass spectrometry to distinguish between different sialic acid linkage types based on their unique mass spectral signatures

Inventive Principle:
Principle #3Local quality

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 enhances the accuracy of sialic acid modification in a linkage-specific manner, reducing unintentional lactonization and enabling precise analysis of sialic acid linkage types in glycans, particularly in O-linked glycans, through improved reaction specificity and efficient sample preparation.

Implementation Method 1

a2,3-sialic acid is lactonized through intramolecular dehydration

Methodology Applied
Scientific EffectIntramolecular dehydration: Condensation

Implementation Method 2

performing a second reaction to ring-open a lactone formed in the first reaction

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentEP3628690B1Method for preparing analytical sample, analysis method, and kit for preparing analytical sample
Publication Date: 2024.01.03 SHIMADZU CORP
  • EP3628690B1 patent drawingFigure 1
  • EP3628690B1 patent drawingFigure 2(a)~2(b)

AI summary

A method for preparing an analytical sample for analyzing a glycan contained in a sample includes: performing a first reaction so that when sialic acid is linked to the glycan, sialic acid of a first linkage type is lactonized and modification different from lactonization is performed on sialic acid of a second linkage type different from the first linkage type; performing a second reaction to ring-open a lactone formed in the first reaction; and performing the first reaction again.