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Biophysical and Biochemical Characterization of Peptide, Protein, and Bioconjugate Products
Published in Sandeep Nema, John D. Ludwig, Parenteral Medications, 2019
Tapan K. Das, James A. Carroll
For N-linked glycans, there are enzymes available which are efficient at removing glycans from the protein. The released N-glycans can then be identified using orthogonal methods. Typically, chemical labeling of released glycans is necessary, since they lack a chromophore and thus a sensitive detection method. A common method for quantifying released N-linked glycans, termed glycan size profiling, employs enzymatic release of the glycans using an enzyme such as PNGaseF, removal of the protein by precipitation or filtration, labeling of the glycans with a fluorophore, and separation of the labeled glycans using NPLC or hydrophilic interaction chromatography (HILIC) with fluorescence detection (Figure 12.4) [49,50]. This method is highly quantitative, since each glycan has one fluorescent label. For this reason, it can be used for routine batch release to ensure consistency in the types and levels of glycans. The identities of the glycans present may be confirmed by a comparison of the elution time of the species with standards or in combination with mass spectrometric detection.
Glycan-Based Nanocarriers in Drug Delivery
Published in Raj K. Keservani, Anil K. Sharma, Rajesh K. Kesharwani, Drug Delivery Approaches and Nanosystems, 2017
Songul Yasar Yildiz, Merve Erginer, Tuba Demirci, Juergen Hemberger, Ebru Toksoy Oner
Carbohydrates play a crucial role in the communication and signaling of organisms. Most of the glycans present on the cell surface and have various important functions for cellular recognition, interaction, adhesion, signal transmission, cellular growth regulation, inflammation, metastasis, and immunologic reactions like bacterial and viral attachment. Cell surface glycans are entry sites for drugs (Ahmad et al., 2015). There are three classes of proteins which serve as a receptor for carbohydrate ligands: enzymes, immunoglobulins and lectins (Yamazaki et al., 2000). Examples of ligand and cell specificity were reported for both mono- and polysaccharides. Mannose and galactose can bind to different type of cells such as dendritic cells, alveolar macrophages or hepatic tumor cells via C type lectin receptors, rhamnose targets human skin cells while functionalized dextran prefers vascular smooth muscle cells and human endothelial cells (Cansell et al., 1999; Chavez-Santoscoy et al., 2012; Chen et al., 2014; Letourneur et al., 2000; Martínez-Ávila et al., 2009).
Cell Physiology
Published in Wei-Shou Hu, Cell Culture Bioprocess Engineering, 2020
A vast majority of recombinant therapeutic proteins are glycoproteins. These proteins have carbohydrates, in the form of branched oligosaccharides, attached to them. The glycosylation of proteins, along with disulfide bond formation, is the most common post-translational modification in recombinant protein products. Glycans are classified as O-linked or N-linked glycans (Panel 3.25). O-glycans attach to the polypeptide through the -OH group of serine or threonine. N-glycans link to protein through the amide group of asparagine. For N-linked glycans, the asparagine is in an Asn-X-Thr/Ser recognition sequence, where X indicates no specificity. For O-glycans, no specific recognition sequence is known.
A comprehensive review of sustainable approaches for synthetic lubricant components
Published in Green Chemistry Letters and Reviews, 2023
Jessica Pichler, Rosa Maria Eder, Charlotte Besser, Lucia Pisarova, Nicole Dörr, Martina Marchetti-Deschmann, Marcella Frauscher
Glycans are complex carbohydrates, linking monosaccharide units through glycosidic bonds, forming linear or branched polymers. They can be either free oligo- or poly-saccharides or bound to proteins (e.g. glycoproteins) and lipids (e.g. glycolipids) (57), and can be found in animals, plants, and fungi (37). As highly functional glycoproteins, so-called mucins, they play a significant part in the field of implant and cartilage wear reduction or prevention, contact lenses, cosmetics, oral salivary (58), synovial fluid (hyaluronan, a glycosaminoglycan) (59), or reducing friction between cornea and eyelid as tear fluid (60,61). In bio-medical application lubricin, a mucin-like glycoprotein lubricin-like synthetic polymers are important boundary lubricants, and naturally occurring alongside hyaluronic acid in the synovial fluid like mucin, lubricin can bind to surfaces and trap water close to the surface, enhancing gliding and reducing friction at the same time (62). Outside the field of bio-tribology, base oils from glycans are not yet studied for their industrial tribological relevance.