Magnetic properties of R(Fe1−xCox)11.3Nb0.7 (R=Y,Ho) compounds

The molecular orientation of antibodies immobilized on solid surfaces plays a significant role in the sensitivity of immunoassays and efficiency of protein isolation using antibody-decorated nanoparticles. Optimally, nearly all antibody binding sites should be available to bind. Here we report for the first time an LC-MS/MS approach to probe antibody orientation directly, utilizing sterically restricted proteolysis. Trypsin-decorated magnetic beads (MBs, 1.5 μm) were much larger than average antibody-free areas (55 × 55 nm) of oriented antibodies on MBs, restricting proteolysis to mainly Fab regions. Randomly attached antibodies on MB surfaces served as controls. The tryptic-hydrolyzed peptides were quantified using LC-MS/MS peptide analysis as markers for average positions of Fc and Fab of antibodies on the beads. Different patterns of digestion rates were found due to proteolysis of the oriented and nonoriented antibodies on MBs. For oriented antibodies, the peptides from outer Fab regions gave a much higher digestion rate than those from Fc regions, while for randomly immobilized antibodies digestion rates for Fab and Fc peptides were similar. This novel approach is a useful and convenient tool to characterize antibody orientation for immunoassays and other applications. The relative degree of orientation can be assessed using a metric R o denoting amount of Fab marker peptides found divided by Fc + Fab marker peptides × 100%. Oriented antibodies on the MBs also provided more efficient antigen capture compared to randomly immobilized antibodies.

show abstract

“…The different slopes are due to the different electrospray ionization efficiencies and variable fragmentation patterns of each peptide. 33…”

Section: Tryptic Peptide Identification and Quantitationmentioning

confidence: 99%

Restricted Proteolysis and LC-MS/MS To Evaluate the Orientation of Surface-Immobilized Antibodies

et al. 2019

View full text Add to dashboard Cite

show abstract

“…This extract has also a gastro-protective benefit, which may be due to its anti-acid effect; it contains anti-spasmodic constituents mediating their effect through cholinergic receptors and blocking Ca 2+ influx. In addition to the many researches in the medical field [8][9][10][11][12][13][14] that recognize and support the importance of plants' components in health, there have been researches for novel compounds as inhibitors of metal corrosion extracted from natural and no toxic substances [4,15]. These include testing at the protection of copper against the phenomenon of corrosion in natural sea water [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Ziziphus lotus as Green Inhibitor of Copper Corrosion in Natural Sea Water

Oukhrib

Issami

Ibrahimi

et al. 2017

Port. Electrochim. Acta

View full text Add to dashboard Cite

This work ultimately pays careful consideration to a method that respects the environment, and that can be developed across the accumulation of research to reduce the corrosion of metals in sea water. Extracts of Ziziphus lotus (wild jujube) were tested as a corrosion inhibitor of copper in sea water, using polarization methods and weight loss measurements. We also present by SEM the morphology of copper surface analyzed after immersion in inhibited and uninhibited electrolytes. The inhibition efficiency of Ziziphus lotus extracts was calculated and compared. We note good agreement between these methods. The obtained results revealed that the tested inhibitor significantly reduced the kinetics of the corrosion process of copper. Its efficiency increases with the concentration, and attained 93% at 5 g/L. The effect of temperature on the corrosion behavior of copper in natural sea water was also studied in the range of 293 K and 323 K, to determine thermodynamic data of activation.

show abstract