Proteins

Protein ladders are a set of standards known as molecular weight proteins that are utilized to identify the approximate size of a protein molecule run on a PAGE gel electrophoresis. The challenges in running the ladders are the choice of appropriate protein standard as it is used as visual evidence of protein migration, transfer efficiency, and positive control. Suitable protein markers can be selected on the basis of required properties and applications, i.e., fluorescent ladder, IEF, 2D SDS-PAGE ladder, natural ladder with an isoelectric point, and optimized ladders for Western Blot chemiluminescence detection. The key factors for running a distinct protein ladder are buffer conditions, charge/voltage at migration time, and the gel's concentration.

Protein ladders are a set of standards known as molecular weight proteins that are utilized to identify the approximate size of a protein molecule run on a PAGE gel electrophoresis. The challenges in running the ladders are the choice of appropriate protein standard as it is used as visual evidence of protein migration, transfer efficiency, and positive control. Suitable protein markers can be selected on the basis of required properties and applications, i.e., fluorescent ladder, IEF, 2D SDS-PAGE ladder, natural ladder with an isoelectric point, and optimized ladders for Western Blot chemiluminescence detection. The key factors for running a distinct protein ladder are buffer conditions, charge/voltage at migration time, and the gel's concentration.

Get tips on using RIPA Lysis Buffer (ProteinSimple) to perform Protein isolation Tissue - Mouse aorta

Get tips on using RIPA Lysis Buffer (ProteinSimple) to perform Protein isolation Tissue - Mouse cardiac tissue

The most widely used method for protein quantification is by spectrophotometry. The concentration of the protein in the samples is measured at an absorbance of 280 nm. The absorbance of the sample protein is then plotted against a standard curve. This method allows for total protein quantification in a sample (cell and tissue extracts). Before analysing the concentration of protein in the sample, it is important to choose the right test method.  For high protein concentration samples (above 5 - 160 mg/ml) the best method is to use the Biuret test. For low concentrations samples (between 1 - 2000µg/ml) the best methods are Lowry assay, BCA assay, Bradford assay and coomassie blue (for exact sensitivity of the test kits you use, refer to manufacturer's protocol). If the samples contain detergents like Triton X-100 then BCA assay is the best choice. For samples that have proteins larger than 3 KDa in size Bradford assay is the best choice. Each method has advantages and disadvantages, plan your analysis considering your sample characteristics.

The most widely used method for protein quantification is by spectrophotometry. The concentration of the protein in the samples is measured at an absorbance of 280 nm. The absorbance of the sample protein is then plotted against a standard curve. This method allows for total protein quantification in a sample (cell and tissue extracts). Before analysing the concentration of protein in the sample, it is important to choose the right test method.  For high protein concentration samples (above 5 - 160 mg/ml) the best method is to use the Biuret test. For low concentrations samples (between 1 - 2000µg/ml) the best methods are Lowry assay, BCA assay, Bradford assay and coomassie blue (for exact sensitivity of the test kits you use, refer to manufacturer's protocol). If the samples contain detergents like Triton X-100 then BCA assay is the best choice. For samples that have proteins larger than 3 KDa in size Bradford assay is the best choice. Each method has advantages and disadvantages, plan your analysis considering your sample characteristics.

Protein ladders are a set of standards known as molecular weight proteins that are utilized to identify the approximate size of a protein molecule run on a PAGE gel electrophoresis. The challenges in running the ladders are the choice of appropriate protein standard as it is used as visual evidence of protein migration, transfer efficiency, and positive control. Suitable protein markers can be selected on the basis of required properties and applications, i.e., fluorescent ladder, IEF, 2D SDS-PAGE ladder, natural ladder with an isoelectric point, and optimized ladders for Western Blot chemiluminescence detection. The key factors for running a distinct protein ladder are buffer conditions, charge/voltage at migration time, and the gel's concentration.

Get tips on using QIAGEN Proteinase K (10 ml) to perform RNA isolation / purification Cells - primary mouse morula cells

Flow cytometry is an immunophenotyping technique whereby sing cell suspensions are stained for either cell surface markers or intracellular proteins by fluorescently-labelled antibodies and analyzed with a flow cytometer, where fluorescently-labelled molecules are excited by the laser to emit light at varying wavelengths, which is then detected by the instrument. There are several key criteria which are required to be kept in mind while designing a flow experiment- 1. Antibody titration (optimal dilution of antibodies should be calculated in order to avoid over- or under- saturated signals for proper detection of surface and intracellular markers), 2. Precision (3 or more replicates of the sample should be used per experiment), 3. Specificity (proper isotype controls should be included in the experiment), 4. Day-to-day variability (experiments should be repeated 3 or more times to ensure consistency and avoid variability due to flow cytometer settings), 5. Antibody interaction (Fluorescence minus one or FMO should be used, which is the comparison of signals from panel minus one antibody vs. the full panel), and 6. Antibody stability (fluorescently-labelled antibodies should be stored at 4C).

Flow cytometry is an immunophenotyping technique whereby sing cell suspensions are stained for either cell surface markers or intracellular proteins by fluorescently-labelled antibodies and analyzed with a flow cytometer, where fluorescently-labelled molecules are excited by the laser to emit light at varying wavelengths, which is then detected by the instrument. There are several key criteria which are required to be kept in mind while designing a flow experiment- 1. Antibody titration (optimal dilution of antibodies should be calculated in order to avoid over- or under- saturated signals for proper detection of surface and intracellular markers), 2. Precision (3 or more replicates of the sample should be used per experiment), 3. Specificity (proper isotype controls should be included in the experiment), 4. Day-to-day variability (experiments should be repeated 3 or more times to ensure consistency and avoid variability due to flow cytometer settings), 5. Antibody interaction (Fluorescence minus one or FMO should be used, which is the comparison of signals from panel minus one antibody vs. the full panel), and 6. Antibody stability (fluorescently-labelled antibodies should be stored at 4C).