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Current Concepts of Implantation and Decidualization
Published in Gabor Huszar, The Physiology and Biochemistry of the Uterus in Pregnancy and Labor, 2020
The importance of N-linked glycoproteins was provisionally reaffirmed by demonstrating the irreversible inhibition of trophoblast adhesion, outgrowth, and Con A binding in blastocysts incubated in the presence of tunicamycin which interferes with protein glycosylation.45,70 The incorporation of mannose was preferentially reduced (80%) compared to glucosamine (28%) and leucine (18%); the synthesis of the carbohydrate-deficient proteins was essentially normal. The results obtained by others71 fail to confirm the tunicamycin effect. Questions have also been raised about the significance of the reduction in protein synthesis which is accompanied by a decrease in membrane-bound ribosomes.72 However, the amounts of cycloheximide which cause the same reduction in total protein synthesis, as does tunicamycin (18%), do not affect the adhesion and outgrowth of treated blastocysts.45 The possibility of tunicamycin cytotoxicity should always be evaluated. The issue deserves further investigation which will include the use of specific proteases and glycosidases to separate the role of glycosylation from protein synthesis in trophoblast adhesion and outgrowth.
Fibrinolysis and Diabetes Mellitus
Published in Pia Glas-Greenwalt, Fibrinolysis in Disease Molecular and Hemovascular Aspects of Fibrinolysis, 2019
Michael W. Mansfield, Peter J. Grant
Protein glycosylation is due to the binding of glucose to protein by a nucleophilic reaction resulting in a Schiff base that then undergoes an Amadori rearrangement.81 The extent to which protein glycosylation occurs is dependent upon the duration and magnitude of protein exposure to glucose. This binding may be reversible, giving rise to early glycosylation products such as glycosylated hemoglobin, which is used as a measure of glycemic control over the preceding 6 to 8 weeks, the time taken by the early glycosylation reaction to reach equilibrium. Glucose binds particularly at the free ∊-amino group residue of protein lysine residues.81
What are the Golgi apparatus? How are they involved in the secretion of proteins? Describe this process in relation to mast cells
Published in Nathaniel Knox Cartwright, Petros Carvounis, Short Answer Questions for the MRCOphth Part 1, 2018
Nathaniel Knox Cartwright, Petros Carvounis
Functionally, the Golgi apparatus play an important role in carbohydrate synthesis and post-translational protein modification. They can be thought of as a sorting and dispatching station for products of the endoplasmic reticulum. Of particular note is their role in protein glycosylation. Transport vesicles carry molecules from one cisterna to the next within the Golgi apparatus.
Proteomic approaches to assist in diagnosis and prognosis of oral cancer
Published in Expert Review of Proteomics, 2021
Jamile De Oliveira Sá, Luciana Daniele Trino, Ana Karina Oliveira, Ariane Fidelis Busso Lopes, Daniela Campos Granato, Ana Gabriela Costa Normando, Erison Santana Santos, Leandro Xavier Neves, Carolina Moretto Carnielli, Adriana Franco Paes Leme
Finally, through the covalent attachment of carbohydrates (glycans) to specific amino acid residues, protein glycosylation plays important regulatory and modulatory roles in diverse pathophysiological processes, matched by the diverse and complex glycan structure [105,106]. In mammals, glycans are attached to asparagine, called N-glycans (in N-X-S/T, X ≠ P consensus sequences), and to serine/threonine residues, the O-glycans, the two major classes of protein glycosylation [85]. Glycome profiling by MS can elucidate structural features of glycans that are difficult to determine while the sugar is still attached to the protein. Thus, integrated glycome and glycopeptide analysis can provide complementary information, with in-depth knowledge of the micro- and macroheterogeneity of protein glycosylation [107].
Novel chimerized IgA CD20 antibodies: Improving neutrophil activation against CD20-positive malignancies
Published in mAbs, 2020
Mitchell Evers, Toine Ten Broeke, J.H. Marco Jansen, Maaike Nederend, Firas Hamdan, Karli R. Reiding, Saskia Meyer, Petra Moerer, Iris Brinkman, Thies Rösner, Robert Jan Lebbink, Thomas Valerius, Jeanette H.W. Leusen
Heterogeneity in protein glycosylation influences the function, pharmacokinetics and safety of biological therapeutics, and it is therefore a critical attribute.15 Because IgA1 contains 2 N-glycosylation sites per heavy chain, the number of different glycans found was more diverse in comparison to IgG1, although heterogeneity remained limited between antibodies. IgA2 antibodies incorporate five distinct N-glycosylation sites on each heavy chain, but has the advantage over IgA1 that it is not O-glycosylated and is not associated with development of IgA nephropathy. The two different antibodies of the IgA2 isotype analyzed in this study differed in their N-glycosylation pattern. However, more antibodies, stable cell line development, and testing of different batches is required to get a clearer image regarding this important drug property.
Proteomics for cancer drug design
Published in Expert Review of Proteomics, 2019
Amanda Haymond, Justin B. Davis, Virginia Espina
Glycosylation remains an understudied and underappreciated aspect of protein post-translational modification. However, as biosimilars continue to be developed, the demand for glycosylation characterization increases. Differences that arise in immunogenicity studies will be traced back to glycosylation fingerprints obtained through these characterization workflows. These structure/function analyses will expand knowledge of the effects of different glycan profiles in patients with differing genomes, phenotypes, and immune states. Biosimilar manufacturers will likely correlate features of the host cell organisms and cell culture conditions responsible for generating their protein to the final glycosylation profiles they observe. We can expect biosimilar development to expand our working knowledge of protein glycosylation structure/function relationships and to drive research into how the sugar code is written and delivered to proteins in vivo.