Sialic acids are negatively charged monosaccharides, what are found on the non-reducing termini of glycans. The key role in product stability and efficacy, thus, sialic acids are often defined in glycoprotein therapeutic products. There exist two most common sialic acids in biopharmaceuticals, the one is N-acetyl-neuraminic acid (Neu5Ac) and the other one is N-glycolyl-neuraminic acid (Neu5Gc). The sialic acid mentioned above are both important to the firmness and 3D conformation of glycoproteins, they are involved in many biological interactions. Sialic acids often have a crucial functional collision, for example, sialylation of the N-glycans on IgG increases anti-inflammatory activity and by stopping uptake by the asialoglycoprotein-receptor located on liver cells, the presence of sialic acids enhances the serum half-life of glycoproteins. Sialic acids preserve the N-acetyl, N-glycolyl and O-acetylation are released from glycoproteins by mild acid hydrolysis using conditions.
Figure 1: Sialic acidsAcetylation is the most commonly modification of sialic acids. O-acetylation decreases the kinetics of enzyme-catalysed desialylation of glycans. Since the wealth and type of sialylation influences the expression of therapeutic glycoproteins, for example, serum half-life, immunogenicity, activity. Under milder acid hydrolysis conditions, many LC-based methods start with the release of the targeted sialic acids. The most liable to change monosaccharides are the family of sialic acids, which are usually chain-terminating substituents. Thus, these are commonly released first by either mild acid hydrolysis or enzyme digestion and with detection of pulsed amperometric, it can be illustrated with great sensitivity by using high pH anion-exchange chromatography. The released sialic acids can be derivatized with DMB, the 1,2-diamino-4,5-methylenedioxybenzene-2HCl dye. High pH anion-exchange chromatography with pulsed amperometric detection is a frequently used method for accurate judgement of the two most common sialic acids found on glycoprotein oligosaccharides, N-acetylneuraminic acid and N-glycolylneuraminic acid. With more and more requires to quickly screen samples from expression cell line and growth condition optimization experiments, shorter analysis times are needed for all analyses, including sialic acid analysis.
Creative Proteomics has a strict workflow to analyze siliac acid to meet your requirements.
