Unveiling Protein Relative Molecular Mass Determination: Comprehensive Analysis of Common Methods

Proteins are important functional molecules in the body, and the determination of their relative molecular mass is crucial for understanding their structure and function.

 

Gel Electrophoresis

Gel electrophoresis is a commonly used method for determining protein relative molecular mass. It separates protein samples into different bands, and by comparing the migration distance of the bands with that of a standard with a known molecular weight, the relative molecular weight of the test protein can be inferred.

 

1. SDS-PAGE

SDS-PAGE is a method based on polyacrylamide gel electrophoresis. It uses the anionic surfactant SDS to negatively charge proteins, causing them to migrate in an electric field according to the size of the molecular weight. By comparing with a standard with a known molecular weight, the relative molecular weight of the test protein can be determined.

 

2. Polyacrylamide Gel Electrophoresis

Polyacrylamide gel electrophoresis is a common protein separation method. By electrophoresing protein samples in a gel and based on the molecular weight and charge characteristics of the proteins, they form different bands in the gel, which can be used to infer the relative molecular weight of the proteins.

 

Mass Spectrometry

Mass spectrometry is a highly sensitive method for determining protein relative molecular mass. It ionizes protein samples and analyzes them in a mass spectrometer. Based on the mass-to-charge ratio and abundance of the ions, the relative molecular weight of the protein can be inferred.

 

1. MALDI-TOF Mass Spectrometry

MALDI-TOF mass spectrometry is a common mass spectrometry analysis method. It mixes the protein sample with a matrix, then uses laser desorption ionization, followed by analysis in a time-of-flight mass spectrometer. Based on the mass-to-charge ratio and abundance of the ions, the relative molecular weight of the protein can be inferred.

 

2. ESI-MS Mass Spectrometry

ESI-MS mass spectrometry is a common mass spectrometry analysis method. It ionizes protein samples in an electrospray ion source and then analyzes them in a mass spectrometer. Based on the mass-to-charge ratio and abundance of the ions, the relative molecular weight of the protein can be inferred.

 

Optical Methods

Optical methods are a very convenient method for determining protein relative molecular mass. By measuring the absorbance of the protein at a specific wavelength, and according to colorimetry or turbidimetry, the relative molecular weight of the protein can be inferred.

 

1. Colorimetry

Colorimetry is a common optical method. By measuring the absorbance of the protein at a specific wavelength, and according to a standard with a known concentration and a colorimetric curve, the relative molecular weight of the test protein can be inferred.

 

2. Turbidimetry

Turbidimetry is a common optical method. By measuring the light scattering of suspended particles in the protein solution, and according to a standard with a known concentration and a turbidimetric curve, the relative molecular weight of the test protein can be inferred.

 

The determination of protein relative molecular mass is an important step in biopharmaceutical research. This article introduced commonly used methods for determining protein relative molecular mass, including gel electrophoresis, mass spectrometry, and optical methods. These methods have their advantages and disadvantages, and researchers can choose the appropriate method for determining protein relative molecular mass according to their experimental needs.