Part II: Development of Mass Spectrometry and Its Application in Biological Research

Types of Commonly Used Mass Spectrometers

The subjects of biological research are generally complex macromolecules, including proteins, nucleic acids, sugars, lipids, and various small molecules. The nature of various types of biomolecules also varies widely. Therefore, various types of mass spectrometers are used in biological research. The common used ones for biological research include quadrupole mass spectrometer, time of flight mass spectrometer, ion trap mass spectrometer and ion cyclotron resonance mass spectrometer.

Time of Flight Mass Spectrometer (TOF)

The mass-to-charge ratio of ions determined by this type of mass spectrometer is derived by analyzing the time of flight of the ions in the vacuum flight tube. After continuous improvement, the TOF mass spectrometer has greatly improved in resolution and precision. The accuracy can reach PPM level after the post-correction procedure, and the detected ion mass range can reach several hundred thousand.

Ion Trap Mass Spectrometer




The ion trap mass spectrometer is a tandem mass spectrometer. The ion trap is the core of the mass spectrometer and is both a collision cell and a mass analyzer. Ion accumulation is stored prior to analysis, so the advantages of ion trap mass spectrometry lies in ion storage and selection.

Ion Cyclotron Resonance (ICR) Mass Spectrometer



ICR mass spectrometer is designed based on the characteristics of the ions moving in a magnetic field. ICR mass spectrometer is the instrument with high resolution and high accuracy in these types of mass spectrometers. Obitrap is a typical representative of high precision mass spectrometer.

Applications of Mass Spectrometry in Biological Research

Detection of Small Molecules in Biological Metabolism

Mass spectrometry has a long-term development in the detection of small molecules, and the measurement and analysis methods of small molecules are also quite mature. At present, mass spectrometry can accurately determine a variety of small biological molecules, including amino acids, fatty acids, organic acids and their derivatives, monosaccharides, prostaglandins, thyroxine, bile acids, cholesterol and steroids, biogenic amines, lipids, carbohydrates , vitamins, trace elements, etc.

Detection of Biological Macromolecules

Proteins, sugars, nucleic acids, and lipids are the main components of living organisms and the function of life activities. Most biological research is carried out around these types of biological macromolecules. Although mass spectrometry of macromolecules is more complex for smaller molecules, the analysis of these biomacromolecules becomes more accurate and faster with the rapid development of mass spectrometry.

Drug Analysis 

The compositions of drugs vary widely. For example, the modification of a key site of antibody drugs may have a great impact on the efficacy of drugs. Therefore, it is difficult to analyze biopharmaceuticals with traditional techniques. Thanks to the high efficiency and accuracy of mass spectrometry, mass spectrometry is commonly used to analyze amino acid sequence of drugs such as glycoproteins such as biopeptides and proteins. In addition, mass spectrometry can also be used for natural medicine, drug metabolism research and Chinese medicine composition analysis.

Microbial Identification

There are many species of microorganisms, and the bacterial protein sequence is also different due to the differences in the genetic sequences of different species of microorganisms. Mass spectrometry is the very peptide fingerprint in the determination of a microorganism. Then,  compare it with the database information to identify the identity of the microorganism. In addition, mass spectrometry can also perform specific carbohydrates analysis or esters produced by certain microorganisms to identify target microorganisms. 

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