Some Advanced Techniques on Proteins

1. Two Advanced Techniques on Proteins Protein gel electrophoresis Protein gel electrophoresis is an easy way to isolate proteins before they are detected or analyzed downstream. Proteins that can be identified by gel electrophoresis mainly include isozymes and storage proteins (which can be divided into alcohol soluble proteins, gluten, albumin and globulin, etc.). The composition of these proteins is determined by heredity and is not affected by environment.Differences in its composition can reflect variety in genotypes, so it is also called "biochemical fingerprint" of varieties. In variety identification, electrophoresis method must take the crop varieties differences in genetic structure into consideration, there are generally two principles: (1) A direct comparison between varieties of protein components, this usually applies to analyze polymorphic loci encoding proteins, such as the gliadin , these protein genotype directly reflected in the electrophoresis,Thus the variety can be identified by comparing the presence or absence of specific bands on the gel (2) Indirect comparison of the occurrence frequency of interspecific protein-band phenotypes is generally applicable to proteins or enzymes encoded by a single gene locus, like isozymes, whose electrophoresis map is only the phenotype of the protein or enzyme gene, not the enzyme gene or genotype itself. In accordance with the above principles, it is advisable to adopt the corresponding fingerprint identification method for self-pollinated crops, cross-pollinated crops, cross-pollinated crops, hybrids or F1 hybrid and clonal varieties between the inter-parental lines among varieties or inbred lines. Then after Protein gel electrophoresis, we’re supposed to gain significant information from the image. Gel image analysis makes use of image analysis system, the digital camera will be placed inside. The ultraviolet light or white light would illuminate the images into the computer. Then through the analysis of the gel corresponding software, it can finish protein gel image analysis, the final gel bands peak can be obtained as well as molecular weight, the number of base pairs, area, height, location, or the total sample volume. Protein identification One of the core contents of proteomics is protein identification. Image analysis based on bidirectional gel electrophoresis can preliminarily cooperate with protein quantification, apparent molecular weight, isoelectric point and other characteristics of tissue cells, but the structure and function of proteins must be identified in other techniques. At the moment, the identification technology with biomass spectrum as the core is gradually formed. Protein microsequencing and amino acid composition analysis are also used in expression pattern analysis. Currently available methods for studying the functional mode of proteome include yeast double hybridization, phage display, biosensor chip mass spectrometry, and site-specific mutation technology in protein engineering. These technologies play a role in promoting the development of proteomics. However, a single technique is usually unable to accurately identify a protein, and several techniques are often needed to accurately identify a protein

2. Nowadays, based on biological mass spectrometry for protein identification technology has become one of the supporting technology of proteomics research. Scientists mainly use database search methods for processing the data. A major shortcoming of this approach is that it cannot identify the protein which isn’t in the database, so how to make full use of the mass spectrum data of the meaning of proteome research is very thorny and important. The new protein identification is one aspect of protein identification, a new function according to the sequence and the definition of a protein known degree is divided into three levels; Based on the method of protein identification, the current methods of new protein identification can be divided into two categories: de novo sequencing and similar sequence search combined method as well as the method of searching nucleic acid database such as EST and genome. Different researchers can apply and develop different identification methods for specific purposes, and the identification of new proteins will be improved with the development of proteomics research.