Related Experiment Video
Updated: Jul 19, 2026
12:06
Metabolic Glycoengineering of Sialic Acid Using N-acyl-modified Mannosamines
Published on: November 25, 2017
Structural analysis of naturally occurring sialic acids
Johannis P Kamerling1, Gerrit J Gerwig
1Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, Utrecht, The Netherlands.
Methods in Molecular Biology (Clifton, N.J.)
|October 31, 2006
Summary
This chapter details two main methods for analyzing sialic acids (Sias): gas-liquid chromatography-mass spectrometry for volatile derivatives and high-performance liquid chromatography for fluorescent derivatives.
Area of Science:
- Analytical Chemistry
- Carbohydrate Chemistry
- Biochemistry
Background:
- Sialic acids (Sias) encompass over 62 naturally occurring members.
- Structural analysis of Sias is crucial for understanding their biological roles.
Purpose of the Study:
- To provide a comprehensive overview of current methodologies for sialic acid structural analysis.
- To detail two primary instrumental approaches: GLC-EI/MS and HPLC-ESI/MS.
Main Methods:
- Analysis of volatile sialic acid derivatives using gas-liquid chromatography (GLC) coupled with electron-impact mass spectrometry (EI/MS).
- Analysis of fluorescently labeled sialic acids using high-performance liquid chromatography (HPLC), potentially coupled with electrospray mass spectrometry (ESI/MS).
- Preparation of specific derivatives: trimethylsilylated methyl ester, heptafluorobutylated methyl ester, pertrimethylsilylated, and fluorescent derivatives using 1,2-diamino-4,5-methylenedioxybenzene.
Main Results:
- Detailed GLC, HPLC, EI/MS, and ESI/MS data are provided for the identification of various sialic acid derivatives.
- The presented methodologies enable robust structural elucidation of diverse sialic acids.
Conclusions:
- The chapter offers detailed insights into established analytical techniques for sialic acids.
- These methods are essential for the accurate structural characterization of sialic acid variants.
Related Concept Videos
01:24Oligosaccharide Assembly
Protein glycosylation starts in the ER lumen and continues in the Golgi apparatus. Glycosyltransferases catalyze the addition of sugar molecules or glycosylation of proteins. Usually, these enzymes add sugars to the hydroxyl groups of selected serine or threonine residues to form O-linked glycans or the amino groups of asparagine residues to form N-linked glycans. Different positions on the same polypeptide chain can contain differently linked glycans.
Multiple sugar molecules that may or may...
Multiple sugar molecules that may or may...
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
01:25Protein Glycosylation
Glycosylation, the most common post-translational modification for proteins, serves diverse functions. Adding sugars to proteins makes the proteins more resistant to proteolytic digestion. Glycosylated proteins can act as markers and receptors to promote cell-cell adhesion. Additionally, they have many essential quality control functions in the cell, such as correct protein folding and facilitating transport of misfolded proteins to the cytosol, which can be degraded.
Glycosylation occurs in...
Glycosylation occurs in...
02:17Structure and Nomenclature of Thiols and Sulfides
Thiols and sulfides are sulfur analogs of alcohols and ethers, respectively, where the sulfur atom takes the place of the oxygen atom. Thus, thiols are generally represented as RSH, where R is an alkyl substituent and —SH is the functional group. On the other hand, in sulfides, the central sulfur atom is bonded to two hydrocarbon groups on either side. Depending upon the type of group, sulfides can be either symmetrical or asymmetrical. Both thiols and sulfides display a bent geometry, similar...
01:19Formation of Lipopolysaccharides
Lipopolysaccharides (LPS) are crucial components of the outer membrane of Gram-negative bacteria, serving both structural and functional roles. It contributes to membrane stability and protects bacteria from host immune responses. LPS is composed of three major regions—lipid A, a core oligosaccharide, and an O antigen. The biosynthesis and assembly of LPS involve a highly coordinated set of enzymatic reactions and transport mechanisms. Additionally, LPS is recognized as an endotoxin, triggering...
01:28Structures of Carboxylic Acid Derivatives
Structure of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...