Protein interaction refers to the process by which two or more protein molecules bind to form a protein complex. Generally, proteins do not function alone but work through the coordinated interaction of multiple protein molecules to achieve complex cellular functions. Therefore, focusing on the study of protein interactions is more conducive to exploring the occurrence and development of diseases, finding specific disease prediction treatment methods, and providing new ideas in the research of new drug development. There are many methods for protein interaction analysis. Alpha Lifetech provides protein interaction analysis services, as well as subsequent mass spectrometry identification analysis services of protein/protein mixtures in purified samples such as IP, Co-IP, and GST fusion protein Pull-down based on Liquid Chromatography-Mass Spectrometry (LC-MS/MS).

1. Mass spectrometry analysis of protein interactions
2. Protein interaction analysis combining Co-immunoprecipitation (CO-IP) with mass spectrometry
3. Protein interaction analysis combining GST fusion protein Pull-down with mass spectrometry
4. Protein interaction analysis combining SILAC with Co-immunoprecipitation and mass spectrometry

Co-immunoprecipitation (CO-IP) for Protein Interaction Analysis Co-immunoprecipitation (CO-IP) uses the specificity between antigens and antibodies to detect physiological interactions between proteins. To preserve the protein interactions in cells, non-ionic denaturants are used to lyse the cells. When the cells are lysed, the protein interactions are preserved, and specific antibodies are added to bind to the target proteins in the cells. After adding Protein A/G to form an antibody-protein complex, centrifugation and separation are performed, precipitating the antibody-protein complex, discarding the supernatant, and finally using mass spectrometry to identify the precipitated proteins, thereby proving their interaction. It is only suitable for analyzing stable or strong protein interactions; it is commonly used to identify the interaction between a target protein and another protein or to find unknown proteins that interact with a target protein.

Alpha Lifetech provides optimized solutions for the extraction, expression, and purification of sample proteins to ensure high-quality bait and prey proteins, offering customers high-quality Co-IP protein interaction analysis services and protein mass spectrometry analysis for proteins obtained from Co-IP.

Advantages of Protein Interaction Analysis: Can isolate protein complexes interacting in their natural state. Disadvantages: Lower sensitivity; cannot analyze weak and transient protein interactions.

1. Protein Interaction Analysis Using GST Fusion Protein Pull-down Technique The GST fusion protein pull-down technique uses genetic recombination to insert a GST-tagged vector into target protein A. Glutathione-coated magnetic beads bind with the target fusion protein. After adding cell lysate, interacting proteins are adsorbed by the fusion protein. Excess glutathione is added for elution, and finally, MS technology is used for analysis. This method mainly studies strong or stable protein interactions in vitro; it can identify the direct interaction between two known proteins of interest or find unknown proteins that may interact with the target protein.

As a technology-based scientific research service company, Alpha Lifetech has years of experience in protein interaction analysis services and mass spectrometry identification analysis based on it. Alpha Lifetech provides GST pull-down protein interaction analysis services and Pull-down target protein mass spectrometry identification services. Characterized by strict quality control and a shorter detection cycle, Alpha Lifetech offers customizable one-stop services covering every step of your project from gene synthesis to data reporting.

1. Protein Interaction Analysis Combining SILAC with Co-immunoprecipitation and Mass Spectrometry Using the SILAC method to label experimental and control group cells separately for Co-IP experiments, the immune complex is separated by the specificity of antigen-antibody reaction; then, LC-MS/MS is used for qualitative/quantitative detection of proteins in the immune complex. When the content of a protein in the experimental group reaches a statistical difference compared to the control group, it is determined that this protein interacts with the protein under study, greatly reducing the possibility of false-positive results in protein interaction analysis. The combination of SILAC technology and Co-IP-MS technology can be used for high-throughput quantitative analysis of protein interaction networks under specific conditions.

Alpha Lifetech uses Thermo Fisher’s Q ExactiveHF mass spectrometry platform, Orbitrap Fusion mass spectrometry platform, and Orbitrap Fusion Lumos mass spectrometry platform combined with Nano-LC, to provide SILAC-based CoIP-MS protein interaction analysis service packages.