Protein Analysis FAQ

• • How to Identify the Interacting Proteins of a Specific Protein in Detail

  To systematically identify the interacting proteins of a specific protein, various experimental strategies can be utilized. The most commonly employed protein-protein interaction (PPI) analysis techniques include: 1. Co-Immunoprecipitation (Co-IP) Co-IP is a widely used method for studying direct and stable protein-protein interactions. It employs specific antibodies to precipitate a target protein along with its interacting partners, which are subsequently analyzed using mass spectrometry or Western.......

• • How to Easily Measure Total Sugar and Protein Content in Plants

  Determination of Total Sugar Content 1. Anthrone Method This is a widely adopted method for the determination of total sugar content. Plant samples are first subjected to appropriate pretreatment and extraction, followed by reaction with the anthrone reagent. The reagent interacts with sugars to form a blue-green chromophore, whose absorbance is measured to quantify the sugar concentration. 2. Phenol-Sulfuric Acid Method This is another widely used technique for quantifying total sugars. Following .......

• • Do Proteins With Smaller Relative Molecular Mass Migrate Faster in SDS-Polyacrylamide Gel Electrophoresis

  SDS-PAGE employs an electric field to separate proteins based on their migration through a polyacrylamide gel matrix. SDS (sodium dodecyl sulfate) is an anionic surfactant that binds uniformly to proteins, denaturing them and imparting a consistent negative charge. As a result, protein migration becomes independent of their native charge and is primarily determined by their size (molecular mass). In SDS-PAGE, the migration rate of proteins is chiefly governed by their molecular mass. Proteins with smaller

• • How Are the B Ions and Y Ions Defined in Mass Spectrometry

  B ions and y ions are two common types of fragment ions observed in peptide analysis using tandem mass spectrometry. These ions are generated during the fragmentation process, typically through collision-induced dissociation (CID) or other fragmentation methods. B ions are generated from the amino-terminal (N-terminal) of the peptide chain. When a peptide bond breaks, and the charged fragment includes the N-terminal, the resulting ion is referred to as a b ion.

• • Method Using a DSS Crosslinker for IP and Polymeric Protein WB

  DSS (Disuccinimidyl Suberate) crosslinker is commonly used to stabilize protein-protein interactions, thereby enhancing the efficiency of immunoprecipitation (IP) and subsequent Western Blot (WB) analysis. Below is a protocol for performing IP and crosslinked protein WB analysis using DSS: Crosslinking: 1. Sample Preparation: Extract proteins from cells or tissues and adjust protein concentration. 2. DSS Addition: Add DSS crosslinker to the protein sample. DSS is a widely used reversible crosslinker that...

• • What Is the Principle of Capillary Electrophoresis Purity Analysis (CE-SDS)? What Are the Functions of the Reagents Used

  Capillary Electrophoresis (CE) is a separation technique that leverages electrophoretic principles to differentiate molecules based on their migration rates in an electric field, facilitated by applying high voltage within a narrow capillary. In CE-SDS (Capillary Electrophoresis-Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis), the SDS-PAGE technique is integrated into the capillary electrophoresis system to enable protein sample separation and purity analysis.

• • How to Calculate Protein Loading Amount for SDS-PAGE

  The goal of determining the sample loading volume is to ensure that the protein electrophoresis bands are clearly visible after SDS-PAGE, but not so concentrated that the bands become blurry. First, it is essential to know the protein concentration in your sample. This is typically achieved through protein concentration determination methods such as Bradford, BCA, or Lowry assays. These methods yield a quantifiable measurement of protein concentration, typically expressed in micrograms per microliter.......

• • Optimal Sample Loading Volume for WB Electrophoresis: Determination Factors and Consequences of Overloading or Underloading

  Western Blot (WB) electrophoresis sample loading volume is determined by several factors, including gel size, well capacity, sample concentration, and the abundance of the target protein. Typically, the loading volume ranges from 10 to 30 µL. If the loading volume is too high, the following issues may occur: 1. Sample Overflow Excessive sample may spill into adjacent wells, causing cross-contamination and misinterpretation of results. 2. Blurry Bands Overloading can lead to smeared or indistinct bands......

• • The Differences Between Channel Proteins, Carrier Proteins, and Receptor Proteins

  Channel proteins, carrier proteins, and receptor proteins are all membrane proteins that play critical roles in biological processes such as substance transport and signal transduction. However, their functions and working mechanisms differ. 1. Channel Proteins Channel proteins are proteins that form channels in the cell membrane, allowing specific molecules and ions to pass through. These channels can be either open or closed, depending on the cell’s needs. For example, potassium ion channels selectively..

• • Internal Standard Method and Calibration Curve Analysis in Gas Chromatography

  Gas Chromatography (GC) is a widely used analytical chemistry technique primarily for the qualitative and quantitative analysis of components in mixtures. In GC, the internal standard method and calibration curve method are two commonly used quantification approaches. Internal Standard Method The internal standard (IS) method is a relative quantification technique that corrects the concentration of the target analyte by adding a known concentration of an internal standard. The internal standard should......