Protein Analysis FAQ

• • How to Detect Cyclohexane and Benzene Using GC-MS? Why Can't Their Peaks Be Separated

  When analyzing cyclohexane and benzene using gas chromatography–mass spectrometry (GC-MS), several key steps and factors must be considered to ensure accurate detection and reliable separation: 1. Column Selection The selection of an appropriate capillary column is critical for the effective separation of cyclohexane and benzene. For these compounds, non-polar or moderately polar stationary phases are typically recommended, such as (5%-phenyl)-methylpolysiloxane (DB-5) or 100% polydimethylsiloxane (DB-1).

• • Why Does Polyacrylamide Gel Electrophoresis Have Higher Resolution Than Cellulose Acetate Membrane Electrophoresis

  Polyacrylamide Gel Electrophoresis (PAGE) and Cellulose Acetate Membrane Electrophoresis (CAE) are two commonly used techniques for separating proteins and nucleic acids. The primary distinction between them lies in the composition and pore structure of the separation medium. The reasons why polyacrylamide gel electrophoresis provides higher resolution than cellulose acetate membrane electrophoresis are as follows: 1. Gel Pore Structure The pore size of polyacrylamide gels can be precisely controlled by....

• • How to Detect the Concentration of Peptide Drugs in Serum Using HPLC

  The quantification of peptide drug concentrations in serum using high-performance liquid chromatography (HPLC) typically involves the following steps: 1. Sample Preparation Peptide drugs must first be extracted from the serum. Given the high content of proteins and other components in serum that may interfere with HPLC analysis, pretreatment is essential. Common pretreatment techniques include protein precipitation (e.g., using organic solvents such as ketones or acidic reagents), solid-phase extraction....

• • What Are the Applications of Mass Spectrometry

  Mass spectrometry (MS) is a highly sensitive and accurate analytical technique used for the detection, identification, and quantification of a wide variety of substances. It has found widespread applications across numerous scientific disciplines. The following are several major applications of mass spectrometry: 1. Identification of Compounds Mass spectrometry enables the elucidation of chemical structures and compositions. It is commonly employed in the identification of unknown substances, verification..

• • Why Is There Only a Solvent Peak but No Analyte Peak in GC-MS Standard Run

  In the GC-MS analysis of a standard sample, the observation of a solvent peak without the presence of an analyte peak may result from several potential factors, as outlined below: 1. Sample Preparation Issue Verify that the sample preparation procedure has been correctly performed. Operational errors during the preparation of the standard may occur, for example, the analyte may not have been added to the solvent or was added in an insufficient amount. 2. Syringe Issue Ensure that the syringe is intact......

• • What Are the Methods for Measuring Peptide Molecular Weight Distribution

  The primary methods for determining peptide molecular weight distribution include: Mass Spectrometry (MS) 1. Characteristics As the most commonly employed technique, mass spectrometry enables precise measurement of peptide mass and sequence identification based on peptide fragmentation patterns. It offers high sensitivity, high resolution, and high throughput, while requiring only minimal sample quantities. 2. Applications MS is well-suited for analyzing the molecular weights of complex polypeptide.........

• • Experimental Steps of Mitochondrial Proteomics Analysis

  Mitochondrial proteomics analysis is a vital experimental technique for investigating the types, expression levels, and functions of proteins within mitochondria. The general steps involved in this analysis are summarized below: Sample Preparation 1. Selection of Cells or Tissues Mitochondria are isolated from specific cell lines or tissues, selected according to the experimental objectives, such as heart, liver, or brain. 2. Cell Disruption Cells or tissues are disrupted using mechanical or chemical.......

• • Steps for BS3 Crosslinking

  The process of BS3 crosslinking generally involves the following key steps: 1. Sample Preparation Begin by preparing the protein samples intended for crosslinking. The protein concentration should be properly adjusted, and the sample must be maintained in a compatible buffer system. 2. Preparation of BS3 Solution Dissolve BS3 in an appropriate solvent, such as DMSO or water, to achieve the desired working concentration. 3. Addition of BS3 to the Sample Introduce the prepared BS3 solution into the protein...

• • Blue Native PAGE Protocol

  The experimental procedure for Blue Native PAGE (BN-PAGE) mainly involves the following steps: 1. Sample Preparation Cells are lysed using mild detergents, such as digitonin or n-dodecyl β-D-maltoside, at 4°C to isolate protein complexes for subsequent analysis. 2. Protein Extraction Cellular debris and remnants are removed by centrifugation, and the resulting supernatant, containing the protein extract, is collected. 3. Sample Buffering The protein sample is mixed with an appropriate amount of G-250 dye...

• • What Software Is Generally Used to Process Polypeptide Mass Spectrometry Data

  The following software tools are commonly used to process polypeptide mass spectrometry data: 1. MaxQuant MaxQuant is a comprehensive mass spectrometry data analysis platform specifically developed for proteomic studies, supporting both polypeptide identification and quantification. It is particularly well-suited for high-resolution MS data and features integrated support for isotopic labeling as well as label-free quantification (LFQ) methodologies. 2. Proteome Discoverer Proteome Discoverer, developed....