Search results for "Glycosylation"

ChemInform Abstract: Glycosylation-Induced Asymmetric Synthesis of 1-Substituted Tetrahydroisoquinolines.

2008

Sugar moiety has a direct influence on the secondary structure and properties of sturgeon gonadotropin

2009

Sugar moiety has a direct influence on the secondary structure and properties of sturgeon gonadotropin Sturgeon Acipenser güldenstädti Br. gonadotropic hormone (GTH) β-subunit (β-GTH) was selectively chemically deglycosylated (dg) by anhydrous hydrogen fluoride and trifluoromethane sulfonic acid. Two dgβ-GTH molecular forms retaining 35% (dgβ-GTH1) and 13% (dgβ-GTH2) of their initial carbohydrates were obtained. Investigation of the reassociated α-β hybrid dimers (recombinants) α-GTH+dgβ-GTH1 and α-GTH+dgβ-GTH2 showed that the immunoreactivity with antiserum raised against standard GTH dropped by 22.5%. Hybrid dimers were recognised by the standard GTH antibodies, which indicated that the s…

Stereoselective glycosylation of Alcohols and Silyl Ethers Using Glycosyl Fluorides and Boron Trifluoride Etherate

1985

The stereoselective glycosylation of alcohols and their silyl ethers has been achieved using O-alkyl-, O-acyl-, and acetal-protected glycosyl fluorides of the pyranose and furanose series and boron trifluoride etherate in CH2Cl2.

Response to: Is newly diagnosed diabetes a stronger risk factor than pre‐existing diabetes for COVID ‐19 severity?

2020

OGT and OGA expression in postmenopausal skeletal muscle associates with hormone replacement therapy and muscle cross-sectional area

2013

Protein glycosylation via O-linked N-acetylglucosaminylation (O-GlcNAcylation) is an important post-translational regulatory mechanism mediated by O-GlcNAc transferase (OGT) and responsive to nutrients and stress. OGT attaches an O-GlcNAc moiety to proteins, while O-GlcNAcase (OGA) catalyzes O-GlcNAc removal. In skeletal muscle of experimental animals, prolonged increase in O-GlcNAcylation associates with age and muscle atrophy. Here we examined the effects of hormone replacement therapy (HRT) and power training (PT) on muscle OGT and OGA gene expression in postmenopausal women generally prone to age-related muscle weakness. In addition, the associations of OGT and OGA gene expressions with…

Effects of oxidative modifications induced by the glycation of bovine serum albumin on its structure and on cultured adipose cells

2005

Non-enzymatic glycosylation (glycation) and oxidative damages represent major research areas insofar as such modifications of proteins are frequently observed in numerous states of disease. Albumin undergoes structural and functional alterations, caused by increased glycosylation during non insulin-dependent diabetes mellitus, which is closely linked with the early occurrence of vascular complications. In this work, we first characterized structural modifications induced by the glycation of bovine serum albumin (BSA). A pathophysiological effect of glycated BSA was identified in primary cultures of human adipocytes as it induces an accumulation of oxidatively modified proteins in these cell…

The Role of Fc Receptors on the Effectiveness of Therapeutic Monoclonal Antibodies.

2021

Since the approval of the first monoclonal antibody (mAb) in 1986, a huge effort has been made to guarantee safety and efficacy of therapeutic mAbs. As of July 2021, 118 mAbs are approved for the European market for a broad range of clinical indications. In order to ensure clinical efficacy and safety aspects, (pre-)clinical experimental approaches evaluate the respective modes of action (MoA). In addition to antigen-specificity including binding affinity and -avidity, MoA comprise Fc-mediated effector functions such as antibody dependent cellular cytotoxicity (ADCC) and the closely related antibody dependent cellular phagocytosis (ADCP). For this reason, a variety of cell-based assays have…

Aberrant glycosylation of alpha-dystroglycan causes defective binding of laminin in the muscle of chicken muscular dystrophy.

2005

Dystroglycan is a central component of dystrophin-glycoprotein complex that links extracellular matrix and cytoskeleton in skeletal muscle. Although dystrophic chicken is well established as an animal model of human muscular dystrophy, the pathomechanism leading to muscular degeneration remains unknown. We show here that glycosylation and laminin-binding activity of alpha-dystroglycan (alpha-DG) are defective in dystrophic chicken. Extensive glycan structural analysis reveals that Galbeta1-3GalNAc and GalNAc residues are increased while Siaalpha2-3Gal structure is reduced in alpha-DG of dystrophic chicken. These results implicate aberrant glycosylation of alpha-DG in the pathogenesis of mus…

The effects of post-translational processing on dystroglycan synthesis and trafficking1

2003

Dystroglycan is a component of the dystrophin glycoprotein complex that is cleaved into two polypeptides by an unidentified protease. To determine the role of post-translational processing on dystroglycan synthesis and trafficking we expressed the dystroglycan precursor and mutants thereof in a heterologous system. A point mutant in the processing site, S655A, prevented proteolytic cleavage but had no effect upon the surface localisation of dystroglycan. Mutation of two N-linked glycosylation sites that flank the cleavage site inhibited proteolytic processing of the precursor. Furthermore, chemical inhibition of N- and O-linked glycosylation interfered with the processing of the precursor a…

Delivery of proteins into living cells by reversible membrane permeabilization with streptolysin-O

2001

The pore-forming toxin streptolysin O (SLO) can be used to reversibly permeabilize adherent and nonadherent cells, allowing delivery of molecules with up to 100 kDa mass to the cytosol. Using FITC-labeled albumin, 10 5 –10 6 molecules were estimated to be entrapped per cell. Repair of toxin lesions depended on Ca 2+ -calmodulin and on intact microtubules, but was not sensitive to actin disruption or to inhibition of protein synthesis. Resealed cells were viable for days and retained the capacity to endocytose and to proliferate. The active domains of large clostridial toxins were introduced into three different cell lines. The domains were derived from Clostridium difficile B-toxin and Clo…