Protein quantification by means of a stain-free SDS-PAGE technology without the need for analytical standards: Verification and validation of the method

2016 ◽  
Vol 48 ◽  
pp. 128-134 ◽  
Author(s):  
Wolfgang Holzmüller ◽  
Ulrich Kulozik
Keyword(s):  
Protein Quantification ◽  
Verification And Validation ◽  
Sds Page ◽  
Analytical Standards

scholarly journals Heat and Pressure Treatments on Almond Protein Stability and Change in Immunoreactivity after Simulated Human Digestion

Nutrients ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1679 ◽  
Author(s):  
Elisabetta De Angelis ◽  
Simona Bavaro ◽  
Graziana Forte ◽  
Rosa Pilolli ◽  
Linda Monaci
Keyword(s):  
Protein Stability ◽  
Total Protein ◽  
Protein Pattern ◽  
Protein Quantification ◽  
Protein Profiling ◽  
Enzyme Linked Immunosorbent Assay ◽  
Total Protein Content ◽  
Bioinformatic Tools ◽  
Sds Page ◽  
Allergenic Proteins

Almond is consumed worldwide and renowned as a valuable healthy food. Despite this, it is also a potent source of allergenic proteins that can trigger several mild to life-threatening immunoreactions. Food processing proved to alter biochemical characteristics of proteins, thus affecting the respective allergenicity. In this paper, we investigated the effect of autoclaving, preceded or not by a hydration step, on the biochemical and immunological properties of almond proteins. Any variation in the stability and immunoreactivity of almond proteins extracted from the treated materials were evaluated by total protein quantification, Enzyme Linked Immunosorbent Assay (ELISA), and protein profiling by electrophoresis-based separation (SDS-PAGE). The sole autoclaving applied was found to weakly affect almond protein stability, despite what was observed when hydration preceded autoclaving, which resulted in a loss of approximately 70% of total protein content compared to untreated samples, and a remarkable reduction of the final immunoreactivity. The final SDS-PAGE protein pattern recorded for hydrated and autoclaved almonds disclosed significant changes. In addition, the same samples were further submitted to human-simulated gastro-intestinal (GI) digestion to evaluate potential changes induced by these processing methods on allergen digestibility. Digestion products were identified by High Pressure Liquid Chromatography-High Resolution Tandem Mass Spectrometry (HPLC-HRMS/MS) analysis followed by software-based data mining, and complementary information was provided by analyzing the proteolytic fragments lower than 6 kDa in size. The autoclave-based treatment was found not to alter the allergen digestibility, whereas an increased susceptibility to proteolytic action of digestive enzymes was observed in almonds subjected to autoclaving of prehydrated almond kernels. Finally, the residual immunoreactivity of the GI-resistant peptides was in-silico investigated by bioinformatic tools. Results obtained confirm that by adopting both approaches, no epitopes associated with known allergens survived, thus demonstrating the potential effectiveness of these treatments to reduce almond allergenicity.

Urine protein quantification in stacking gel by SDS-PAGE

2018 ◽  
Vol 40 (4) ◽  
pp. 487-490
Author(s):  
Jia Jia ◽  
Jie Pan ◽  
Hongpan Xu ◽  
Sen Wang ◽  
Bing Bai
Keyword(s):  
Protein Quantification ◽  
Urine Protein ◽  
Sds Page

scholarly journals Protein quantification and visualization via ultraviolet-dependent labeling with 2,2,2-trichloroethanol

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Anand Chopra ◽  
William G. Willmore ◽  
Kyle K. Biggar
Keyword(s):  
Light Exposure ◽  
Covalent Modification ◽  
Protein Quantification ◽  
Visible Range ◽  
Uv Absorbance ◽  
Polyacrylamide Gels ◽  
Fluorescent Emission ◽  
Tyrosine Residues ◽  
Sds Page ◽  
Low Volume

Abstract The incorporation of 2,2,2-trichloroethanol in polyacrylamide gels allows for fluorescent visualization of proteins following electrophoresis. Ultraviolet-light exposure, in the presence of this trichlorinated compound, results in a covalent modification of the tryptophan indole ring that shifts the fluorescent emission into the visible range. Based on this principle, we used 2,2,2-trichloroethanol to develop a microplate format protein quantification assay based on the fluorescent signal generated by modified proteins. We also demonstrated a specific fluorescent emission of 2,2,2-trichloroethanol-labeled protein at 450 nm, with a 310 nm excitation, resulting from modification of both tryptophan and tyrosine residues. Following optimization, this protein quantification assay displayed superior sensitivity when compared to UV absorbance at 280 nm (A280), and enabled quantification beyond the linear range permitted by the Bradford method. This 100 μL assay displayed a sensitivity of 10.5 μg in a range up to at least 200 μg. Furthermore, we extended the utility of this method through the development of a 20 μL low-volume assay, with a sensitivity of 8.7 μg tested up to 100 μg, which enabled visualization of proteins following SDS-PAGE. Collectively, these results demonstrate the utility of 2,2,2-trichloroethanol-based protein quantification and demonstrates the protein visualization in polyacrylamide gels based on 2,2,2-trichloroethanol-labeling pre-electrophoresis.

scholarly journals Investigating Toxin Diversity and Abundance in Snake Venom Proteomes

2022 ◽  
Vol 12 ◽  
Author(s):  
Theo Tasoulis ◽  
Tara L. Pukala ◽  
Geoffrey K. Isbister
Keyword(s):  
Snake Venom ◽  
Protein Identification ◽  
Protein Quantification ◽  
Clinical Effects ◽  
Protein Families ◽  
Crude Venom ◽  
Proteome Coverage ◽  
Current State ◽  
Sds Page ◽  
Viper Venoms

Understanding snake venom proteomes is becoming increasingly important to understand snake venom biology, evolution and especially clinical effects of venoms and approaches to antivenom development. To explore the current state of snake venom proteomics and transcriptomics we investigated venom proteomic methods, associations between methodological and biological variability and the diversity and abundance of protein families. We reviewed available studies on snake venom proteomes from September 2017 to April 2021. This included 81 studies characterising venom proteomes of 79 snake species, providing data on relative toxin abundance for 70 species and toxin diversity (number of different toxins) for 37 species. Methodologies utilised in these studies were summarised and compared. Several comparative studies showed that preliminary decomplexation of crude venom by chromatography leads to increased protein identification, as does the use of transcriptomics. Combining different methodological strategies in venomic approaches appears to maximize proteome coverage. 48% of studies used the RP-HPLC →1D SDS-PAGE →in-gel trypsin digestion → ESI -LC-MS/MS pathway. Protein quantification by MS1-based spectral intensity was used twice as commonly as MS2-based spectral counting (33–15 studies). Total toxin diversity was 25–225 toxins/species, with a median of 48. The relative mean abundance of the four dominant protein families was for elapids; 3FTx–52%, PLA2–27%, SVMP–2.8%, and SVSP–0.1%, and for vipers: 3FTx–0.5%, PLA2–24%, SVMP–27%, and SVSP–12%. Viper venoms were compositionally more complex than elapid venoms in terms of number of protein families making up most of the venom, in contrast, elapid venoms were made up of fewer, but more toxin diverse, protein families. No relationship was observed between relative toxin diversity and abundance. For equivalent comparisons to be made between studies, there is a need to clarify the differences between methodological approaches and for acceptance of a standardised protein classification, nomenclature and reporting procedure. Correctly measuring and comparing toxin diversity and abundance is essential for understanding biological, clinical and evolutionary implications of snake venom composition.

scholarly journals Investigation of Heat and Pressure Treatments on Almond Protein Stability and Immunoreactivity after Simulated Human Digestion

2018 ◽  
Author(s):  
Elisabetta De Angelis ◽  
Simona L. Bavaro ◽  
Graziana Forte ◽  
Rosa Pilolli ◽  
Linda Monaci
Keyword(s):  
Total Protein ◽  
Protein Pattern ◽  
Protein Quantification ◽  
Protein Profiling ◽  
Total Protein Content ◽  
Bioinformatic Tools ◽  
Sds Page ◽  
Allergenic Proteins ◽  
The Stability

Almond is worldwide consumed and renowned as a valuable healthy food. In spite of this, it is also a potent source of allergenic proteins able to trigger several mild to life-threatening immunoreactions. Food processing proved to alter biochemical characteristics of proteins, thus affecting the respective allergenicity. In this paper we investigated the effect of autoclaving, preceded or not by a hydration step, on the biochemical and immunological properties of almond proteins. Any variation in the stability and immunoreactivity of almond proteins extracted from the treated materials, were evaluated by total protein quantification, ELISA assay and protein profiling by electrophoresis-based separation (SDS-PAGE). The autoclaving alone was found to weakly affect almond proteins stability, despite what observed for the combination of hydration and autoclaving, which resulted in a loss of approximately 70% of total protein content compared to untreated sample, and in a final negligible immunoreactivity, as well. The final SDS-PAGE protein pattern recorded for almonds hydrated and autoclaved disclosed significant changes. In addition, the same samples were further submitted to in vitro simulated gastro-duodenal (GI) digestion to evaluate potential changes induced by these processing on allergens digestibility. Digestion products were identified by HPLC-HRMS/MS analysis followed by software-based data mining, and complementary information were provided by analyzing the proteolytic fragments lower that 6 kDa in size. The autoclave based treatment was found not to alter the allergens digestibility, whereas an increased susceptibility to proteolytic action of digestive enzymes was observed in almonds subjected to the combination of prehydration and autoclaving. Finally, the residual immunoreactivity of the GI resistant peptides was investigated in-silico by bioinformatic tools, confirming that by following both approaches, no epitopes survived the almond digestion, thus demonstrating the potential effectiveness of these treatments to reduce almond allergenicity.

FPCount protocol - Short protocol v1

2021 ◽  
Author(s):  
Eszter Csibra ◽  
Guy-Bart Stan
Keyword(s):  
Protein Concentration ◽  
Fluorescent Protein ◽  
R Package ◽  
Protein Quantification ◽  
Short Version ◽  
Protein Storage ◽  
Concentration Determination ◽  
Sds Page ◽  
Plate Reader ◽  
Microplate Reader

FPCount is a complete protocol for fluorescent protein calibration, consisting of: 1. FP expression/purification using Thermo's HisPur Cobalt Resin. 2. FP concentration determination in a microplate reader. 3. FP fluorescence quantification in a microplate reader. Results can be analysed with the corresponding R package, FPCountR. This short version uses the ECmax protein quantification protocol, and is only suitable for FPs with entries in FPbase. If you want to verify or validate results, it's recommended you follow the complete protocol, which describes three protein quantification methods. The short protocol also skips the SDS-PAGE steps. If you require these, please see the complete protocol. --- Summary 1. Expression 2. Harvesting/Washing 3. Lysis 4. Fractionation 6. Purification 8. Protein concentration and buffer exchange 9. Quantification of FP concentration (part1) 10. Quantification of FP fluorescence 12. Protein storage 13. Calibration of Plate Reader

3-D organization of fibrinogen receptors using computer reconstruction and whole-mount microscopy

1988 ◽  
Vol 46 ◽  
pp. 30-31
Author(s):  
E. T. O'Toole ◽  
R. R. Hantgan ◽  
J. C. Lewis
Keyword(s):  
Whole Blood ◽  
Colloidal Gold ◽  
Blood Platelets ◽  
Cell Contact ◽  
Computer Assisted ◽  
Adherent Cells ◽  
Differential Centrifugation ◽  
Computer Reconstruction ◽  
Sds Page ◽  
Whole Mount

Thrombocytes (TC), the avian equivalent of blood platelets, support hemostasis by aggregating at sites of injury. Studies in our lab suggested that fibrinogen (fib) is a requisite cofactor for TC aggregation but operates by an undefined mechanism. To study the interaction of fib with TC and to identify fib receptors on cells, fib was purified from pigeon plasma, conjugated to colloidal gold and used both to facilitate aggregation and as a receptor probe. Described is the application of computer assisted reconstruction and stereo whole mount microscopy to visualize the 3-D organization of fib receptors at sites of cell contact in TC aggregates and on adherent cells.Pigeon TC were obtained from citrated whole blood by differential centrifugation, washed with Ca++ free Hank's balanced salts containing 0.3% EDTA (pH 6.5) and resuspended in Ca++ free Hank's. Pigeon fib was isolated by precipitation with PEG-1000 and the purity assessed by SDS-PAGE. Fib was conjugated to 25nm colloidal gold by vortexing and the conjugates used as the ligand to identify fib receptors.

Parallel Reduction of Plasma Levels of High and Low Molecular Weight Kininogen in Patients with Cirrhosis

1999 ◽  
Vol 82 (11) ◽  
pp. 1428-1432 ◽  
Author(s):  
Cheryl Scott ◽  
Francesco Salerno ◽  
Elettra Lorenzano ◽  
Werner Müller-Esterl ◽  
Angelo Agostoni ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Liver Disease ◽  
Liver Function ◽  
Plasma Levels ◽  
Plasma Concentrations ◽  
Normal Subjects ◽  
Low Molecular Weight ◽  
Major Band ◽  
Sds Page ◽  
Normal Controls

SummaryLittle is known about the regulation of high-molecular-weight-kininogen (HK) and low-molecular-weight-kininogen (LK) or the relationship of each to the degree of liver function impairment in patients with cirrhosis. In this study, we evaluated HK and LK quantitatively by a recently described particle concentration fluorescence immunoassay (PCFIA) and qualitatively by SDS PAGE and immunoblotting analyses in plasma from 33 patients with cirrhosis presenting various degrees of impairment of liver function. Thirty-three healthy subjects served as normal controls. Patients with cirrhosis had significantly lower plasma levels of HK (median 49 μg/ml [range 22-99 μg/ml]) and LK (58 μg/ml [15-100 μg/ml]) than normal subjects (HK 83 μg/ml [65-115 μg/ml]; LK 80 μg/ml [45-120 μg/ml]) (p < 0.0001). The plasma concentrations of HK and LK were directly related to plasma levels of cholinesterase (P < 0.0001) and albumin (P < 0.0001 and P < 0.001) and inversely to the Child-Pugh score (P < 0.0001) and to prothrombin time ratio (P < 0.0001) (reflecting the clinical and laboratory abnormalities in liver disease). Similar to normal individuals, in patients with cirrhosis, plasma HK and LK levels paralleled one another, suggesting that a coordinate regulation of those proteins persists in liver disease. SDS PAGE and immunoblotting analyses of kininogens in cirrhotic plasma showed a pattern similar to that observed in normal controls for LK (a single band at 66 kDa) with some lower molecular weight forms noted in cirrhotic plasma. A slight increase of cleavage of HK (a major band at 130 kDa and a faint but increased band at 107 kDa) was evident. The increased cleavage of HK was confirmed by the lower cleaved kininogen index (CKI), as compared to normal controls. These data suggest a defect in hepatic synthesis as well as increased destructive cleavage of both kininogens in plasma from patients with cirrhosis. The decrease of important regulatory proteins like kininogens may contribute to the imbalance in coagulation and fibrinolytic systems, which frequently occurs in cirrhotic patients.

Sign in / Sign up

Export Citation Format

Share Document