scholarly journals Improving the Study of Protein Glycosylation with New Tools for Glycopeptide Enrichment

2021 ◽  
Author(s):  
Minyong Chen ◽  
Steven J. Dupard ◽  
Colleen M. McClung ◽  
Cristian I. Ruse ◽  
Mehul B. Ganatra ◽  
...  
Keyword(s):  
Protein Glycosylation ◽  
Complex Samples ◽  
Selective Enrichment ◽  
Attachment Sites ◽  
Pngase F ◽  
Peptide Mixtures ◽  
Analysis Workflow ◽  
Respective Protein ◽  
New Strategies

High confidence methods are needed for determining the glycosylation profiles of complex biological samples as well as recombinant therapeutic proteins. A common glycan analysis workflow involves liberation of N-glycans from glycoproteins with PNGase F or O-glycans by hydrazinolysis prior to their analysis. This method is limited in that it does not permit determination of glycan attachment sites. Alternative proteomics-based workflows are emerging that utilize site-specific proteolysis to generate peptide mixtures followed by selective enrichment strategies to isolate glycopeptides. Methods designed for the analysis of complex samples can yield a comprehensive snapshot of individual glycans species, the site of attachment of each individual glycan and the identity of the respective protein in many cases. This chapter will highlight advancements in enzymes that digest glycoproteins into distinct fragments and new strategies to enrich specific glycopeptides.

scholarly journals Concurrent chromatographic determination of pseudoephedrine and loratadine from combination syrups and tablets

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Imad Osman Abu Reid
Keyword(s):  
Ammonium Acetate ◽  
Chemical Properties ◽  
Chromatographic Determination ◽  
Analytical Challenge ◽  
Intermediate Precision ◽  
Box Behnken Design ◽  
Complex Samples ◽  
System Suitability ◽  
Nonpolar Compounds

Abstract Background Chromatographic separation of polar and nonpolar compounds when presented in combined dosage forms has always been considered as great analytical challenge. Separation and retention of both polar and nonpolar compounds by the same stationary phase can be a useful approach for analyses of complex samples with such a difference in chemical properties. Loratadine (nonpolar) and pseudoephedrine (polar) are typical examples of this situation. Results The Box–Behnken design was used to optimize the separation process, an efficient separation of loratadine and pseudoephedrine was achieved within 6 min; employing a mixture of 16.0 mM ammonium acetate buffer (pH 4.5) and acetonitrile (23:77, v/v) as isocratic mobile phase, pumped at 1.0 mL/min through a Zorbax cyanopropyl column (250 mm × 4.6 mm, 5 μm), the analytes were detected at 250 nm. Under the same conditions, separation of sodium benzoate preservative co-formulated with the two analytes in syrup formulation was also achieved. The calibration curve demonstrated excellent linearity in the range of 24.6–123.2 μg/mL and 594.8–2974.0 μg/mL for loratadine and pseudoephedrine, respectively with determination coefficient (r2) > 0.999. Conclusion The method’s accuracy bias < 2.0%, repeatability and intermediate precision (%RSD < 2.0%) were verified. In addition, system suitability parameters were found within the acceptable limits. Satisfactory results were obtained upon the application of the validated method to the analysis of commercial tablet and syrup formulations.

Synchronous Luminescence Spectroscopy: Methodology and Applicability

1982 ◽  
Vol 36 (5) ◽  
pp. 576-581 ◽  
Author(s):  
Tuan Vo-Dinh
Keyword(s):  
Direct Determination ◽  
Cost Effective ◽  
Luminescence Spectroscopy ◽  
Second Derivative ◽  
Experimental Conditions ◽  
Complex Samples ◽  
Figures Of Merit ◽  
Synchronous Luminescence Spectroscopy ◽  
Complex Organic

This paper discusses the figures of merit associated with the synchronous luminescence (SL) technique in multicomponent analysis of complex samples. Spectral interferences and experimental factors that influence the choice of experimental conditions are investigated. The efficacy of SL is demonstrated in the direct determination of anthracene and 2-methylanthracene in a raw coal liquid. The application of the second-derivative technique to the SL measurement of organic samples is shown. Special emphasis is directed toward the applicability of the SL technique as a practical and cost-effective screening procedure in the routine analysis of complex organic samples.

scholarly journals Genome-Wide Analysis of Sterol-Lipid Storage and Trafficking in Saccharomyces cerevisiae

2007 ◽  
Vol 7 (2) ◽  
pp. 401-414 ◽  
Author(s):  
Weihua Fei ◽  
Gabriel Alfaro ◽  
Baby-Periyanayaki Muthusamy ◽  
Zachary Klaassen ◽  
Todd R. Graham ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Neutral Lipid ◽  
Lipid Synthesis ◽  
Secretory Protein ◽  
Lipid Storage ◽  
Protein Glycosylation ◽  
Particle Assembly ◽  
Genome Wide ◽  
And Storage

ABSTRACT The pandemic of lipid-related disease necessitates a determination of how cholesterol and other lipids are transported and stored within cells. The first step in this determination is the identification of the genes involved in these transport and storage processes. Using genome-wide screens, we identified 56 yeast (Saccharomyces cerevisiae) genes involved in sterol-lipid biosynthesis, intracellular trafficking, and/or neutral-lipid storage. Direct biochemical and cytological examination of mutant cells revealed an unanticipated link between secretory protein glycosylation and triacylglycerol (TAG)/steryl ester (SE) synthesis for the storage of lipids. Together with the analysis of other deletion mutants, these results suggested at least two distinct events for the biogenesis of lipid storage particles: a step affecting neutral-lipid synthesis, generating the lipid core of storage particles, and another step for particle assembly. In addition to the lipid storage mutants, we identified mutations that affect the localization of unesterified sterols, which are normally concentrated in the plasma membrane. These findings implicated phospholipase C and the protein phosphatase Ptc1p in the regulation of sterol distribution within cells. This study identified novel sterol-related genes that define several distinct processes maintaining sterol homeostasis.

Using a Priori Information in Energy-Dispersive X-Ray Fluorescence Analysis of Complex Samples

1991 ◽  
Vol 35 (B) ◽  
pp. 1205-1209
Author(s):  
I. A. Kondurov ◽  
P. A. Sushkov ◽  
T. M. Tjukavina ◽  
G. I. Shulyak
Keyword(s):  
High Temperature Superconductors ◽  
A Priori ◽  
Fluorescence Analysis ◽  
A Priori Information ◽  
Complex Samples ◽  
X Ray ◽  
Edxrf Analysis ◽  
The Matrix ◽  
Priori Information

In multielement EDXRF analysis of very complex unknowns, some problems in data evaluation may be simplified if one can take into account a priori information on the properties of the incident and detected radiations, and also available data on the matrix of the sample. The number of variables can be drastically shortened in the LSM procedures in this case. One of the best examples of complex unknowns is the determination of the rare earth element content of ores, and most recently in samples of high temperature superconductors (HiTc).

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