Proteomic Mass Spectrometry Technology

Proteins are the main carriers of life activities, and whether proteins are expressed and the amount of expression are closely related to the physiological status and health of organisms. The type, structure, quantity, and modification status of proteins directly affect various functions of organisms. In order to deeply understand the structure and function of proteins, proteomics technology was born.

 

Proteomics technology is actually a technique that uses mass spectrometry to study proteins. The principle is that proteins are digested by proteases to form peptide mixtures. In the mass spectrometer, the peptide mixtures form charged ions. The electric field and magnetic field of the mass spectrometer separate peptide ions with specific mass-to-charge ratios (i.e., M/Z). The detector collects the separated ions and determines the M/Z value of each ion. The mass analyzer can analyze the M/Z of each peptide segment and obtain the M/Z spectrum of all peptide segments of the protein, which is the primary mass spectrum peak diagram of the protein. The ion selection device automatically selects peptide ions with larger intensity for secondary mass spectrum analysis, outputs the secondary mass spectrum peak diagram of the selected peptide segment, and identifies the protein by comparing with the theoretical primary mass spectrum peak diagram and secondary mass spectrum peak diagram produced by the protein after digestion by trypsin.Commonly used proteomics technologies mainly include the following types:

 

Liquid Chromatography Tandem Mass Spectrometry (LC-MS)

LC-MS is the most commonly used proteomics technology. It uses the distribution equilibrium between different substances in the liquid mobile phase and the stationary phase for separation, and then detects the separated components. In protein analysis, high performance liquid chromatography (HPLC) is used to separate complex protein mixtures, and mass spectrometer (MS) is used to detect and analyze HPLC separated protein ions.

 

Capillary Electrophoresis Mass Spectrometry (CE-MS)

Capillary electrophoresis (CE) can separate charged proteins, providing high-resolution and highly efficient separation. MS is used to measure and analyze the mass and structure of proteins obtained by electrophoresis separation.

 

Time of Flight Mass Spectrometry (TOF-MS)

TOF-MS measures their mass based on the flight time of ions in an electric field. Ions produced by the ion source are accelerated into a field-free flight area. The longer the flight time, the greater the mass of the ion. TOF-MS has the characteristics of high sensitivity and high resolution.

 

Tandem Mass Spectrometry (MS/MS)

Combines two or more mass spectrometers for further fragmentation and analysis of selected ions. In the first stage mass spectrometry (MS1), ions of a specific mass are selected to enter the collision chamber for fragmentation, and then the child ions produced by these fragmentation are analyzed in the second stage mass spectrometry (MS2), further providing structure and sequence information of the protein.

 

MALDI-MS

Matrix-assisted laser desorption/ionization (MALDI) technology is used to desorb and ionize proteins from the matrix, suitable for the analysis of large molecules such as proteins and peptides. It has low requirements for samples and can analyze proteins and peptides in complex samples.

 

ESI-MS

Electrospray ionization (ESI) is an ionization technique that converts liquid samples into gaseous ions. It is also one of the most commonly used ionization techniques in LC-MS. The sample solution is sprayed through a high voltage nozzle to form charged droplets, and then the droplets evaporate to leave charged ions. ESI-MS can directly generate multiply charged ions from solution samples, maintain the molecular structure from being destroyed, and is especially suitable for the analysis of proteins and peptides.

 

At present, proteomics technology is widely used for qualitative and quantitative analysis of proteins, research on protein structure and modification, and exploration of protein interactions. MtoZ Biolabs uses Thermo's latest Obitrap Fusion Lumos mass spectrometer combined with Nano-LC nanoscale chromatography technology to accurately analyze proteins in protein extracts, SDS-PAGE protein strips, 2D protein gel spots, pull-down and Co-IP samples, including molecular weight identification, sequence analysis, structure analysis, quantitative analysis, post-translational modification identification, etc. We are committed to providing you with the best one-stop proteomics solution, welcome to consult for free and get more service details!